Page 1 of 34 Print Date: 1994 ENGINE PERFORMANCE FORD MOTOR CO. - SYSTEM & COMPONENT TESTING - EEC-IV 5.0L INTRODUCTION 1994 Ford Mustang 5.0L Eng VIN T GT Before testing separate components or systems, perform procedures in BASIC TESTING - V8 article in the ENGINE PERFORMANCE section. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. NOTE: Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens. NOTE: For wiring diagrams not shown in testing procedures, see WIRING DIAGRAMS. NOTE: In the following testing, circuit diagrams and illustrations are courtesy of Ford Motor Co. AIR INDUCTION SYSTEMS SUPERCHARGER NOTE: Supercharger cannot be overhauled. If supercharger malfunctions, replace entire supercharger assembly. Supercharger Noisy Air or vacuum leaks. Check hoses, tubes and flange joints for leaks. Exhaust leaks. Check rubber tube to EGR valve for looseness and damage. By-pass actuator not opening. Check by-pass vacuum tube for damage, restriction and incorrect routing. Check valve and actuator rod for restriction. Ensure actuator rod rests against lever stop when vacuum is less than 3 in. Hg. Actuator rod should be fully open (horizontal) when vacuum is greater than 8 in. Hg. Low supercharger oil level. Replace supercharger if no oil is present. Contaminated supercharger. Remove outlet adapter. Inspect rotors for foreign objects. Replace supercharger if rotors are damaged.

Page 2 of 34 Gear rattle is normal and does not affect performance. Excessive gear rattle can be caused by actuator valve not opening. Chirping is normal and does not affect performance. Excessive chirping can be caused by rough engine idle and actuator valve not opening. Low Boost Air or vacuum leaks. Check hoses, tubes and flange joints for leaks. Restricted air inlet. Check air filter and air induction system. Supercharger not rotating. Check drive belt. Remove outlet adapter. Inspect rotors for damage and seizure. Replace supercharger if rotors are damaged. By-pass actuator not closing. Check valve and actuator rod for restriction. Ensure actuator rod rests against lever stop when vacuum is less than 3 in. Hg. Insufficient flow from supercharger. Remove outlet adapter. Ensure rotors turn when pulleys are rotated. Replace supercharger if rotors do not turn. High Boost Check for plugged exhaust system. Check for plugged intercooler tubes. Check for correct supercharger pulleys. Oil Leakage Some oil seepage may occur with mileage. Ensure PCV system is not restricted. Ensure oil fill plug is tight. Check oil level, and top off as necessary. If oil loss is excessive, replace supercharger. COMPUTERIZED ENGINE CONTROLS POWERTRAIN CONTROL MODULE (PCM) Ground Circuits 1. Using a DVOM, check for continuity to ground on PCM terminals No. 40 and 60. See Fig 1. Resistance should be zero ohms. If resistance is not zero ohms, repair open to ground. 2. Using a voltmeter, touch negative lead of voltmeter to a good ground. Touch positive lead of voltmeter to each ground terminal. With vehicle running, voltmeter should indicate less than 0.5 volt. If voltmeter reading is greater than 0.5 volt, check for open circuit, corrosion and loose connection on ground lead. Power Circuits Using a voltmeter, check for battery voltage between PCM terminal No. 1 (KAPWR) and ground. See Fig 1. Check for battery voltage at terminals No. 37 and 57 (VPWR). If battery voltage is not present, EEC power relay is not supplying power. See CIRCUIT TEST B in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section.

Page 3 of 34 Fig 1: PCM Connector Terminal ID ENGINE SENSORS & SWITCHES NOTE: For additional sensor testing specifications, proceed to SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE section. A/C CUTOUT Faults in system or circuits should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, See CIRCUIT TEST KM in TESTS W/CODES - EEC-IV (5.0L) article for testing in the ENGINE PERFORMANCE section. BAROMETRIC PRESSURE (BARO) SENSOR Faults in barometric pressure sensor or circuit should set a diagnostic trouble code. See QUICK TEST in the appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If code has not been set, see CIRCUIT TEST DF in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for sensor specifications. CYLINDER IDENTIFICATION (CID) CID is integral with Camshaft Position (CMP) sensor or Crankshaft Position (CKP) sensor. Disconnect sensor connector. See CID SENSOR LOCATION table. Check connector for wear or corrosion. For additional circuit testing information, see CIRCUIT TEST DR in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section and PIN VOLTAGE CHARTS article in the PIN VOLTAGE TABLE. ENGINE COOLANT TEMPERATURE (ECT) SENSOR ECT sensor requires a 5-volt reference signal during engine operation. With sensor disconnected, sensor may be checked by measuring resistance between sensor terminals. For specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE section. For additional sensor circuit testing, see CIRCUIT TEST DA in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section.

Page 4 of 34 EGR ATMOSPHERIC (EGRA) SOLENOID Faults in sensor or circuit should set a diagnostic trouble code. If diagnostic trouble code has not been set, disconnect sensor. Measure resistance between sensor terminals. Replace sensor if resistance is not 30-70 ohms. EGR POSITION (EGRP) SENSOR Faults in sensor or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST DD in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for testing. EGR VACUUM REGULATOR (EVR) SOLENOID Faults in sensor or circuit should set a diagnostic trouble code. If diagnostic trouble code has not been set, disconnect sensor. Measure resistance between sensor terminals. Replace sensor if resistance is not 20-70 ohms. EGR VACUUM (EGRV) SOLENOID Faults in sensor or circuit should set a diagnostic trouble code. If diagnostic trouble code has not been set, disconnect sensor. Measure resistance between sensor terminals. Replace sensor if resistance is not 30-70 ohms. EGR VALVE POSITION (EVP) SENSOR Faults in sensor or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST DN in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for testing. HEATED GAS OXYGEN SENSOR (HO2S) Vehicle may be equipped with one or 2 HO2S sensors. They are located in exhaust pipe, upstream of catalytic converters. Faults in sensor or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, ensure none of these conditions exist: Moisture inside sensor/harness connector. HO2S sensor coated with contaminants. Sensor circuit open or shorted to ground. If necessary, see CIRCUIT TEST H in the appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for additional specifications and circuit testing procedures. INERTIA FUEL SHUTOFF (IFS) SWITCH 1. Turn ignition off. Locate IFS switch in rear of vehicle. Ensure IFS switch reset button is not in upper (tripped) position. Using a jumper lead, ground FP terminal at Diagnostic Link Connector (DLC). See Fig 3. 2. Turn ignition on. Leaving inertia switch connector attached, check voltage at IFS switch connector. If 10.5 volts is not present, repair circuit. If 10.5 volts is present at one terminal only, replace IFS switch. 3. If 10.5 volts is present at both terminals, turn ignition off. Disconnect IFS switch connector. Ensure IFS switch reset button is in down position. Measure resistance between IFS switch terminals.

Page 5 of 34 4. Resistance should be 5 ohms or less. If resistance is more than 5 ohms, replace switch. For additional circuit testing information, refer to CIRCUIT TEST J in the appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. INTAKE AIR TEMPERATURE (IAT) SENSOR IAT sensor requires a 5-volt reference signal during engine operation. With sensor disconnected, sensor may be checked by measuring resistance between sensor terminals. For specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE section. For additional testing information, see CIRCUIT TEST DA in appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. KNOCK SENSOR (KS) KS is located on cylinder block. Sensor is tested by substitution or by manually generating a knock to ensure sensor will set a diagnostic trouble code. Faults in sensor or circuit should set a diagnostic trouble code. See QUICK TEST in the appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST DG in the TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for additional sensor circuit testing procedures. MASS AIRFLOW (MAF) SENSOR 1. Faults in MAF sensor or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, install Breakout Box (T83L-50-EEC-IV), leaving PCM connected. Start engine, and allow it to idle. 2. Measure voltage between test pin No. 50 and negative battery terminal. If voltage is not.36-1.50 volts, replace MAF sensor. If voltage is.36-1.50 volts, MAF sensor is okay. See CIRCUIT TEST DC in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for circuit testing. POWER STEERING PRESSURE SWITCH (PSPS) Faulty PSPS or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST FF in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for testing. PRESSURE FEEDBACK (PFE) EGR SENSOR & DIFF PFE (DPFE) SENSOR Faults in sensor or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST DL in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for testing. THROTTLE POSITION (TP) SENSOR Faults in TP sensor or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see THROTTLE POSITION (TP) SENSOR in the ADJUSTMENTS - V8 article in the ENGINE PERFORMANCE section for adjusting procedures. For testing procedures, see CIRCUIT TEST DH in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. VEHICLE SPEED SENSOR (VSS)

Page 6 of 34 1. Faults in VSS or circuit should set diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. Disconnect VSS electrical connector if diagnostic trouble code has not been set. 2. Using DVOM, measure resistance between sensor terminals. Replace sensor is resistance is not 190-250 ohms. If sensor is 190-250 ohms, see CIRCUIT TEST DP in TESTS W/CODES - EEC- IV (5.0L) article in the ENGINE PERFORMANCE section for additional circuit testing. MODULES, RELAYS & SOLENOIDS MODULES Constant Control Relay Module (CCRM) Faults in CCRM or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST X in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for CCRM testing. Variable Control Relay Module (VCRM) Faults in VCRM or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST XB in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for testing. RELAYS NOTE: On 5.0L, fuel pump relay is located inside Constant Control Relay Module (CCRM). For CCRM test procedures, proceed to CIRCUIT TEST X in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. Turn ignition off. Disconnect fuel pump relay. Set DVOM on 200-ohm scale. On ISO relays, measure resistance between terminals No. 85 and 86. See Fig 2. On all other relays, measure resistance between VPWR pin and FUEL PUMP circuit pin at fuel pump relay. On all relays, both readings should be 40-85 ohms. Set DVOM to 10-k/ohm scale. On ISO relays, measure resistance between terminal No. 85 and terminals No. 30 and 87. On all other relays, measure resistance between FUEL PUMP circuit terminal and both POWER-TO-PUMP and B+ pins at fuel pump relay. On all relays, if all readings are more than 10,000 ohms, relay is okay. If any reading is 10,000 ohms or less, replace fuel pump relay.

Page 7 of 34 Fig 2: Fuel Pump Relay Connector Terminal ID SOLENOIDS 1. Secondary Air Injection By-Pass/Diverter (AIRB/AIRD) Solenoids Faults in secondary air injection solenoids or circuits should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, disconnect solenoid to be tested. 2. Measure resistance between sensor terminals. If resistance is not 50-100 ohms, replace solenoid. If resistance is 50-100 ohms, solenoid is okay. See CIRCUIT TEST KC in the appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for additional circuit testing. Canister Purge (CANP) Solenoid 1. Faults in CANP solenoid or circuit should set a diagnostic trouble code. See QUICK TEST in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, disconnect CANP solenoid harness connector. 2. Measure resistance across CANP solenoid terminals. If resistance is not 30-90 ohms, replace CANP solenoid. If resistance is 30-90 ohms, disconnect vacuum hose at CANP solenoid on manifold vacuum side. 3. Apply 16 in. Hg vacuum to manifold vacuum side of solenoid. CANP solenoid should hold vacuum for 20 seconds. If CANP solenoid does not hold vacuum for 20 seconds, replace CANP solenoid. If CANP solenoid holds vacuum for 20 seconds, solenoid is okay. If additional testing is

Page 8 of 34 EGR Solenoid required, proceed to CIRCUIT TEST KD in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for circuit testing. See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS. Idle Air Control Solenoid Faults in idle air control solenoid or circuits should set a diagnostic trouble code. Refer to QUICK TEST in appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST KE in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for testing. Intake Air Control Solenoid For testing procedure, see AIR INDUCTION SYSTEMS in this article. FUEL SYSTEMS NOTE: In following test procedures, KOEO refers to Key On Engine Off and KOER refers to Key On Engine Running. FUEL SYSTEM PRESSURE RELEASE 1. Remove fuel cap to release fuel tank pressure. Remove relief valve cap. Relief valve is located on fuel supply manifold. Using Fuel Pressure Gauge (T80L-9974-B), release fuel pressure from relief valve (Schrader valve). 2. If fuel pressure gauge is not available, disconnect electrical connector to IFS switch. For IFS switch location, see INERTIA FUEL SHUTOFF (IFS) SWITCH location table under INERTIA FUEL SHUTOFF (IFS) SWITCH. Crank engine for 15 seconds to reduce system pressure. INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION Application Mustang Location Lower Left Rear Of Trunk FUEL DELIVERY Fuel Pump Relay See RELAYS under MODULES, RELAYS & SOLENOIDS. Constant Control Relay Module (CCRM) See CIRCUIT TEST X in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. Variable Control Relay Module (VCRM) See CIRCUIT TEST XB in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section.

Page 9 of 34 CAUTION: Inspect fuel system for leaks and damage before testing fuel pump. 1. System Integrity Check Perform the following checks: 1. Ensure Inertia Fuel Shutoff (IFS) switch reset button is not in upper (tripped) position. See INERTIA FUEL SHUTOFF (IFS) SWITCH LOCATION table. 2. Ensure battery is fully charged and fuel related fuses are okay. 3. Check fuel tank contents and fuel gauge accuracy. If any fault is detected, repair as necessary. If system checks are okay, go to next step. 2. Check Fuel Pressure Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE. Install fuel pressure gauge. Connect a jumper wire between ground and fuel pump test terminal at Data Link Connector (DLC). See Fig 3.Turn ignition on to activate pump. Check and record fuel pressure. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. Proceed to appropriate step as indicated: 1. If fuel pressure is within specification, go to next step. 2. If fuel pressure is low, go to step 10). 3. If fuel pressure is high, go to step 11).

Page 10 of 34 Fig 3: Data Link Connector Terminal ID 3. Check For Fuel Pressure Leak-Down Operate fuel pump as in step 2) for a minimum of 30 seconds. Turn ignition off and disconnect jumper wire from DLC. Wait one minute then check fuel pressure gauge. If fuel pressure remains within 5 psi of specification, go to step 5). If fuel pressure does not remain within 5 psi of specification, go to next step. 4. Check Fuel Pressure Regulator Diaphragm Turn ignition off. Ensure vacuum hose is connected to fuel pressure regulator. Start and run engine for 10 seconds. Stop engine, and wait 10 seconds. Start and run engine for 10 seconds. Stop engine. Remove vacuum hose from pressure regulator. If fuel is present in vacuum port, replace fuel pressure regulator and repeat step 2). If fuel is not present, either fuel injectors are leaking down or check valve in fuel pump is defective. Repair as necessary and repeat step 2). 5. Check Fuel Pressure With Engine Load Ensure vacuum hose is still disconnected from pressure regulator. Observe pressure gauge while driving vehicle with heavy accelerations. If fuel pressure remains within 3 psi during test, reconnect vacuum hose to pressure regulator and go to next step. If fuel pressure does not remain within 3 psi, go to step 8).

Page 11 of 34 6. Check Fuel Pressure Regulator Install vacuum gauge to intake manifold. Start engine. Observe vacuum and fuel pressure gauge while accelerating and decelerating engine. When engine is accelerating, vacuum reading should decrease and fuel system pressure should increase. When engine is decelerating, vacuum reading should increase and fuel system pressure should decrease. If readings are as specified, fuel system is okay and test is compete. If gauge readings are not as specified, go to next step. 7. Check Vacuum Supply Disconnect and plug fuel pressure regulator hose. Attach vacuum pump to fuel pressure regulator. Start engine. Apply vacuum to pressure regulator while observing fuel pressure gauge. If fuel pressure changes as vacuum changes, repair restriction in vacuum supply hose. If fuel pressure does not change as vacuum changes, replace fuel pressure regulator. 8. Check Fuel Filter Check for plugged fuel filter. Replace filter as necessary, and repeat step 2). If filter is okay, replace fuel pump. 9. Check Voltage At Both Pump Speeds Turn ignition off. Connect DVOM between ground and either terminal at Inertia Fuel Shutoff (IFS) switch. IFS switch is located in left side of trunk. Start engine. Voltage reading should be about 9 volts at idle and 13 volts at 3500 RPM. If voltage is as specified, check for faulty fuel pump ground connection. Repair as necessary. If ground is okay, replace fuel pump. 10. Check For Low Pressure Causes Turn ignition off. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Disconnect fuel return hose from pressure regulator. Using a separate piece of fuel hose, connect one end of hose to fuel return port at pressure regulator and place other end of hose into a suitable container. With jumper wire still connected to DLC as in step 2), turn ignition on (engine off). If fuel pressure is still low and fuel is being returned into container, replace pressure regulator. If fuel pressure is still low and fuel is not being returned into container, replace fuel pump and repeat step 2). 11. Check For High Pressure Causes Turn ignition off. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE. Disconnect fuel return hose from pressure regulator. Using a separate piece of fuel hose, connect one end of hose to fuel return port at pressure regulator and place other end of hose into a suitable container. With jumper wire still connected to DLC as in step 2), turn ignition on (engine off). If fuel pressure is within specification, replace pressure regulator and repeat step 2). For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If fuel pressure is not within specification, go to next step. 12. Check Fuel Return System Turn ignition off. Fuel return hose should still be disconnected at pressure regulator. Disconnect fuel return hose near fuel tank. Apply 3-5 psi of regulated air to return line port at pressure regulator. If air flows freely through return line, replace fuel pump and repeat step 2). If air does not flow freely, check fuel return system for restrictions. Repair as necessary and repeat step 2). FUEL CONTROL Fuel Injector Check 1. Connect tachometer to engine. Run engine at idle. Observe tachometer and disconnect and reconnect injectors individually. When disconnected, each injector should cause a momentary drop in engine speed of at least 100 RPM. Engine RPM drop should only be momentary as PCM will attempt to reestablish correct idle RPM. 2. Replace any injectors which do not cause sufficient drop in engine speed. When test is complete, check idle speed. Refer to emission control specifications on decal in engine compartment or see IDLE SPEED in ADJUSTMENTS - V8 article in the ENGINE PERFORMANCE section.

Page 12 of 34 Fuel Injector Circuit Disconnect injector harness connectors. Using digital ohmmeter, measure resistance between each injector terminal. Individual injector resistance should be 13-19 ohms. IDLE CONTROL SYSTEM Faults in idle control system or circuit should set a diagnostic trouble code. See QUICK TEST in the appropriate TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST KE in TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for testing. IGNITION SYSTEM NOTE: For additional information and descriptions, see IGNITION SYSTEM in THEORY/OPERATION - EEC-IV 5.0L article in the ENGINE PERFORMANCE section. IGNITION SYSTEM ACRONYMS Acronym (1) B + Or B (+) Definition Battery Positive B- Or B (-) Battery Negative C1, C2, C3 Coil Drive (Coils 1, 2 & 3) DI EI (2) FTO ICM IDM IGND KOEC KOEO KOER PCM PIP PWR GND SPOUT VPWR Or VBAT Distributor Ignition System Electronic Ignition (High Data Rate Or Low Data Rate) Filtered Tach Output Ignition Control Module Ignition Diagnostic Monitor (Diagnostic Signal To PCM) Ignition Ground (Low Current Ground Reference) Key On Engine Cranking (Testing Condition) Key On Engine Off (Testing Condition) Key On Engine Running (Testing Condition) Powertrain Control Module (EEC-Processor, Computer, Processor) Profile Ignition Pick-Up (Camshaft Position Sensor Signal) Power Ground Circuit To ICM Spark Output (PCM Spark Control Signal) Battery Power Or Battery Voltage (1) Not all circuits and components are used in all systems.

Page 13 of 34 (2) EI is a distributorless ignition system. IGNITION SYSTEM IDENTIFICATION Application Mustang System DI DI SYSTEM Preliminary Check Perform following preliminary checks: Visually inspect engine compartment to verify vacuum hoses and spark plug wires are properly routed and securely connected. Examine all wiring harnesses and connectors for damage. Ensure ICM is securely mounted to distributor base or cowl. Ensure battery is fully charged. All accessories should be off during diagnosis. Test Equipment Following test equipment should be used in DI system tests. Spark Tester (D81P-6666-A Or D89P-6666-A) Digital Volt-Ohmmeter (DVOM) 12-Volt Test Light Remote Starter Switch EEC-IV Diagnostic Cable (007-00097) EEC-IV Breakout Box (T83L-50-EEC-IV) Inductive Timing Light Diagnostic Aids PINPOINT TESTS A, AA, AAA, B and C are intended to diagnose hard faults. Intermittent failures may be difficult to diagnose using these procedures. Following information should be noted during testing: All voltage readings given in test procedures are based on values obtained using a standard DVOM such as Rotunda (007-00001) or Fluke (20 or 70 Series). DO NOT use RMS type meter. When instructed to inspect a wiring harness, perform both a visual inspection and a continuity test. When making voltage checks, ground connections should be made at negative battery terminal or cast iron surface of engine. When making measurements on a wiring harness or connector, perform a wiggle test while measuring. When making voltage checks, ground readings are defined as a value of less than 1.0 volt. Battery voltage is defined as a value of more than 10 volts. Circuits are identified in all capitals, for example: PIP. Manufacturer's breakout box overlay test terminals are identified by a "J" prefix, for example: J15 (PIP). This indicates test terminal number and circuit identification. Test procedures are intended to identify faulty components or wiring while fault is present. If complaint is an intermittent condition, refer to TESTS W/O CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section.

Page 14 of 34 NOTE: Start all diagnostics with QUICK TEST. See TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. These tests are dependent on results and diagnostic trouble codes received during QUICK TEST. DI PINPOINT TEST INDEX Application Pinpoint Test/Step No Start & No Codes Present Distributor Mounted ICM A/1 Remote Mounted ICM AA/1 No Start & Code 211 Or 212 Present (PIP At PCM Fault) Distributor Mounted ICM A/1 Remote Mounted ICM Vehicle Runs Normal Until SPOUT In-Line Connector Disconnected (1) AA/1 AAA/1 Code 212 (Engine Runs, IDM Missing B/1 Code 213 (Timing Incorrect, SPOUT Open, Poor Fuel Economy Or Poor Driveability) C/1 (1) Vehicles with remote mounted ICM only. PINPOINT TEST A: NO START DISTRIBUTOR MOUNTED ICM 1. Check For Codes Perform QUICK TEST. See TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble codes are present, service codes as required. If codes are not present, go to next step. 2. Check Battery Turn ignition on. Check battery voltage. If battery voltage is less than 12 volts, service battery as necessary. If battery voltage is more than 12 volts, go to next step. 3. Check For Spark While Cranking Using Neon Bulb Spark Tester (D89P6666-A), check for spark at coil wire while cranking. If spark is present, go to step 9). If spark is not present, go to next step. 4. Check Power To ICM Turn ignition off. Connect EEC-IV Diagnostic Cable (007-00097) to EEC- IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position. Apply DI overlay on breakout box. WARNING: DO NOT connect EEC-IV Diagnostic Cable and PCM to EEC-IV Breakout Box simultaneously. Turn ignition on. Put DVOM on DC voltage scale. Measure voltage between J5 (ICM PWR) and J7 (B -). If voltage is 10 volts or less, repair open in ICM PWR circuit to ICM. If voltage is more than 10 volts, put DVOM on AC voltage scale and go to next step.

Page 15 of 34 Fig 4: EEC-IV Diagnostic Cable (007-00097)- Installation Arrangement ID (DI) 5. Check PIP Signal Measure voltage between J7 (B -) and J15 (PIP) while cranking engine. If AC voltage is not 3.0-8.5 volts, go to step 11). If AC voltage is 3.0-8.5 volts, go to next step. 6. Check SPOUT Signal Measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If AC voltage is not 3.0-8.5 volts, go to step 15). If AC voltage is 3.0-8.5 volts, go to next step. 7. Check COIL PWR At Coil Turn ignition off. Connect diagnostic cable to ignition coil wiring harness connector. Leave ignition coil disconnected. Set DVOM on DC voltage scale. Turn ignition on. Measure voltage between J2 (COIL PWR) and J7 (B -). If DC voltage is 10 volts or less, repair open circuit in ignition coil circuit. If DC voltage is more than 10 volts, go to next step. 8. Check COIL- Signal Turn ignition off. Connect B+ lead of diagnostic cable to positive battery terminal. Connect test light to J1 (B +) and J3 (COIL-). Crank engine. If test light does not flash brightly, go to step 23). If test light flashes brightly, replace coil. Remove test equipment, reconnect all components, and repeat QUICK TEST. 9. Check For Spark Using Neon Bulb Spark Tester (D89P6666-A), check for spark at each spark plug wire while cranking. If spark is consistent at all spark plug wires, go to next step. If spark is not consistent, service distributor cap, rotor, plugs or plug wires.

Page 16 of 34 10. Check Spark Plugs Remove and inspect spark plugs. Replace plugs as necessary. If spark plugs are okay, no-start condition is not ignition related. See TESTS W/O CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for symptom diagnosis. 11. Check PIP Signal From ICM If AC voltage is not 3.0-8.5 volts in step 5), turn diagnostic cable switch to PIP OPEN position. Measure voltage between J7 (B -) and J15 (PIP) while cranking engine. If AC voltage is not 3.0-8.5 volts, go to step 14). If AC voltage is 3.0-8.5 volts, go to next step. 12. Check For Short To Power In PIP Circuit Turn ignition off. Turn diagnostic cable switch to NORMAL position. Put DVOM on DC voltage scale. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness connector. Disconnect PCM connector. Turn ignition on. Measure voltage between J7 (B -) and J15 (PIP). If DC voltage is 0.5 volt or more, repair short in PIP circuit between PCM and ICM. If DC voltage is less than 0.5 volt, go to next step. 13. Check For Short To Ground In PIP Circuit Turn ignition off. Measure resistance between J7 (B -) and J15 (PIP). If resistance is more than 10,000 ohms, replace PCM. If resistance is 10,000 ohms or less, repair short in PIP circuit between PCM and ICM. 14. Check ICM Resistance If AC voltage was not 3.0-8.5 volts in step 11), turn ignition off. Remove ICM from distributor. Measure resistance of ICM circuits. See ICM RESISTANCE table. See Fig 5. If resistance is not as specified, replace ICM. If resistance is as specified, check stator and wiring inside distributor. Repair as necessary. If stator and wiring are okay, replace Camshaft Position (CMP) sensor. ICM RESISTANCE Between Terminals Ohms PIP (In)& PIP (Out) Less Than 150 CMP PWR & ICM PWR Less Than 150 GND & PIP (In) More Than 500 GND & IGN GND Less Than 5 PIP (In)& CMP PWR 900-1500

Page 17 of 34 Fig 5: Distributor Mounted ICM Terminal ID 15. Check SPOUT Signal If AC voltage was not 3.0-8.5 volts in step 6), turn diagnostic cable switch to SPOUT OPEN position. Measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If AC voltage is 3.0-8.5 volts, replace ICM. Remove test equipment, reconnect all components, and repeat QUICK TEST. If AC voltage is not 3.0-8.5 volts, go to next step. 16. Check SPOUT Circuit Voltage Turn ignition off. Turn diagnostic cable switch to NORMAL position. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness connector. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT). If DC voltage is less than 0.5 volt, go to step 18). If DC voltage is 0.5 volt or more, go to next step.

Page 18 of 34 17. Check For Short To Power In SPOUT Circuit Turn ignition off. Disconnect PCM. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT). If DC voltage is less than 0.5 volt, go to step 20). If DC voltage is 0.5 volt or more, repair short to power in SPOUT circuit between PCM and ICM. 18. Check SPOUT Circuit Resistance Turn ignition off. Measure resistance between test pin J7 (B -) and J10 (SPOUT). If resistance is 10,000 ohms or less, go to next step. If resistance is more than 10,000 ohms, go to step 20). 19. Check For Short To Ground In SPOUT Circuit Disconnect PCM. Measure resistance between J7 (B -) and J10 (SPOUT). If resistance is still 10,000 ohms or less, repair short to ground in SPOUT circuit between PCM and ICM. If resistance is more than 10,000 ohms, go to next step. 20. Check For Open In PIP Circuit Ensure ignition is still off and PCM is disconnected. Measure resistance between breakout box test pin J15 (PIP) and PCM wiring harness connector terminal No. 56 (PIP). If resistance is 5 ohms or more, repair open in PIP circuit between PCM and ICM. If resistance is less than 5 ohms, go to next step. 21. Check IGN GND At PCM Connect diagnostic cable to ICM. Measure resistance between breakout box test pin J7 (B -) and PCM wiring harness connector terminal No. 16 (IGN GND). If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, go to next step. 22. Check For Open In IGN GND Circuit Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness connector. Measure resistance between breakout box test pin J9 (IGN GND) and PCM wiring harness connector terminal No. 16 (IGN GND). If resistance is less than 5 ohms, replace ICM. If resistance is 5 ohms or more, repair open in IGN GND circuit between PCM and ICM. 23. Check For Open In COIL- Circuit If test light does not flash brightly in step 8), disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness connector. Disconnect diagnostic cable from positive battery cable. Measure resistance between J3 (COIL-) and J4 (COIL-). If resistance is 5 ohms or more, repair open in COIL- circuit between ignition coil and ICM. If resistance is less than 5 ohms, go to next step. 24. Check For Short To Power In COIL- Circuit Put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J3 (COIL-) and J7 (B -). If DC voltage is 5.5 volts or more, repair short to power in COIL- circuit between ignition coil and ICM. If DC voltage is less than 5.5 volts, go to next step. 25. Check For Short To Ground In COIL- Circuit Turn ignition off. Measure resistance between J3 (COIL-) and J7 (B -). If resistance is 10,000 ohms or less, repair short in COIL- circuit between ignition coil and ICM. If resistance is more than 10,000 ohms, replace ICM.

Page 19 of 34 Fig 6: Remote Mounted ICM System Diagnostics (Mustang) PINPOINT TEST AA: NO START REMOTE MOUNTED ICM 1. Check For Codes Perform QUICK TEST. See TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble codes are present, service codes as necessary. If codes are not present, go to next step. 2. Check Battery Turn ignition on. Check battery voltage. If battery voltage is less than 12 volts, service battery as necessary. If battery voltage is more than 12 volts, go to next step. 3. Check For Spark Using Neon Bulb Spark Tester (D89P6666-A), check for spark at coil wire while cranking. If spark is present, go to step 9). If spark is not present, go to next step. 4. Check For ICM Power Turn ignition off. Connect EEC-IV Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. See Fig 4. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position. Put DI overlay on breakout box. WARNING: DO NOT connect EEC-IV Diagnostic Cable and PCM to EEC-IV Breakout Box simultaneously.

Page 20 of 34 Turn ignition on. Put DVOM on DC voltage scale. Measure voltage between J5 (ICM PWR) and J7 (B -). If voltage is 10 volts or less, repair open in ICM PWR circuit to ICM. See Fig 6. If voltage is more than 10 volts, go to next step. 5. Check PIP Signal Put DVOM on AC voltage scale. Measure voltage between J7 (B -) and J15 (PIP) while cranking engine. If AC voltage is not 3.0-8.5 volts, go to step 11). If AC voltage is 3.0-8.5 volts, go to next step. 6. Check SPOUT Signal Measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If AC voltage is not 3.0-8.5 volts, go to step 18). If AC voltage is 3.0-8.5 volts, go to next step. Fig 7: Remote Mounted ICM Terminal ID 7. Check COIL PWR At Coil Turn ignition off. Connect diagnostic cable to ignition coil wiring harness connector. Leave ignition coil disconnected. Put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J2 (COIL PWR) and J7 (B -). If voltage is 10 volts or less, repair open in ignition coil circuit. If voltage is more than 10 volts, go to next step. 8. Check COIL- Signal Turn ignition off. Connect B+ lead of diagnostic cable to positive battery terminal. Connect test light between J1 (B +) and J3 (COIL-). Crank engine. If test light does not flash brightly, go to step 27). If test light flashes brightly, replace ignition coil. 9. Check For Spark Using Neon Bulb Spark Tester (D89P6666-A), check for spark at each spark plug wire while cranking. If spark is consistent at all spark plug wires, go to next step. If spark is not consistent, service distributor cap, rotor, plugs or plug wires. 10. Check Spark Plugs Remove and inspect spark plugs. Replace plugs as necessary. If spark plugs are okay, no-start condition is not ignition related. See TESTS W/O CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. 11. Check For CMP Power At CMP Sensor If AC voltage between J7 and J15 was not 3.0-8.5 volts in step 3), connect diagnostic cable CMP (PIP) sensor tee to CMP sensor and wiring harness connector. Set DVOM to DC voltage scale. Measure voltage between J7 (B -) and J22 (PIP PWR). If voltage is 10 volts or less, repair open in PIP PWR circuit. If voltage is more than 10 volts, go to next step.

Page 21 of 34 12. Check For PIP From CMP Sensor Turn diagnostic cable switch to PIP OPEN position. Set DVOM to AC voltage scale. While cranking engine, measure voltage between J7 (B -) and J34 (PIP A). If AC voltage is not 3.0-8.5 volts, check PIP wiring and connector. Repair as necessary. If wiring and connector are okay, replace Camshaft Position (CMP) sensor. If AC voltage is 3.0-8.5 volts, go to next step. 13. Check PIP With ICM Disconnected Turn ignition off. Turn diagnostic cable switch to NORMAL position. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness connector. While cranking engine, measure voltage between J7 (B -) and J34 (PIP A). If AC voltage is 3.0-8.5 volts, replace ICM. If AC voltage is not 3.0-8.5 volts, go to next step. 14. Check PIP With PCM Disconnected Disconnect PCM. While cranking engine, measure voltage between J7 (B -) and J34 (PIP A). If AC voltage is 3.0-8.5 volts, replace PCM. If AC voltage is not 3.0-8.5 volts, go to next step. 15. Check PIP A To PCM For Short To Power Turn ignition off. Disconnect diagnostic cable from CMP sensor. Leave diagnostic cable attached to CMP sensor wiring harness connector. Put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J7 (B -) and J34 (PIP A) If voltage is 0.5 volt or more, repair PIP A circuit short to power between CMP sensor and PCM or ICM. If voltage is less than 0.5 volt, go to next step. 16. Check PIP B To ICM For Short To Power Measure voltage between J7 (B -) and J41 (PIP B). If voltage is 0.5 volt or more, repair PIP B circuit short to power between CMP sensor and PCM. If voltage is less than 0.5 volt, go to next step. 17. Check PIP For Short To Ground Turn ignition off. Measure resistance between J7 (B -) and J41 (PIP B). If resistance is more than 10,000 ohms, repair short to ground in PIP A circuit between PCM and CMP sensor. If resistance is 10,000 ohms or less, repair short to ground in PIP B circuit between CMP sensor and ICM. Testing is complete. NOTE: If engine starts in step 18), continue testing. 18. Check For SPOUT In Harness If AC voltage between J7 and J10 was not 3.0-8.5 volts in step 6), turn diagnostic cable switch to SPOUT OPEN position. Measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If AC voltage is 3.0-8.5 volts, replace ICM. If AC voltage is not 3.0-8.5 volts, go to next step. 19. Check For SPOUT High Turn ignition off. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness connector. Turn diagnostic cable switch to NORMAL position. Put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT). If voltage is 0.5 volt or more, go to next step. If voltage is less than 0.5 volt, go to step 21). 20. Check For Short To Power In SPOUT Turn ignition off. Disconnect PCM. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT). If voltage is less than 0.5 volt, go to step 23). If voltage is 0.5 volt, or more, repair short in SPOUT circuit between PCM and ICM. 21. Check For Short To Ground In SPOUT If voltage is less than 0.5 volt DC in step 19), turn ignition off. Measure resistance between J7 (B -) and J10 (SPOUT). If resistance is 10,000 ohms or less, go to next step. If resistance is more than 10,000 ohms, go to step 23). 22. Check For Short To Ground In SPOUT Harness Disconnect PCM. Measure resistance between J7 (B -) and J10 (SPOUT). If resistance is still 10,000 ohms, or less, repair short in SPOUT circuit between PCM and ICM. If resistance is more than 10,000 ohms, go to next step.

Page 22 of 34 23. Check For Open PIP Turn ignition off. Disconnect PCM. Set DVOM to AC voltage scale. Measure voltage between J7 (B -) and J56 (SPOUT). If AC voltage is not 3.0-8.5 volts, go to step 26). If AC voltage is 3.0-8.5 volts, go to next step. 24. Check IGN GND At PCM Turn ignition off. Reconnect diagnostic cable to ICM. Measure resistance between breakout box test pin J7(B -) and PCM wiring harness connector terminal No. 16 (IGN GND). If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, go to next step. 25. Check IGN GND At CMP Sensor Connect diagnostic cable to CMP sensor and sensor wiring harness connector. Measure resistance between J7 (B -) and J35 (IGN GND). If resistance is less than 5 ohms, repair open in IGN GND circuit between PCM and CMP sensor. If resistance is 5 ohms or more, repair IGN GND wire or replace CMP sensor (open circuit inside CMP sensor). 26. Check PIP A At CMP Sensor If AC voltage is not 3.0-8.5 volts in step 23), turn diagnostic cable switch to PIP OPEN position. Connect diagnostic cable between CMP sensor and sensor wiring harness connector. Crank engine while measuring voltage between J7 (B -) and J34 (PIP A). If AC voltage is 3.0-8.5 volts, repair PIP circuit between CMP sensor and PCM. If AC voltage is not 3.0-8.5 volts, repair PIP wire or replace CMP sensor (open circuit inside CMP sensor). 27. Check For COIL- Open In Harness If test light does not flash brightly in step 8), turn ignition off. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness connector. Disconnect diagnostic cable from positive battery cable. Measure resistance between J3 (COIL-) and J4 (COIL-). If resistance is 5 ohms or more, repair open in COIL- circuit between ignition coil and ICM. If resistance is less than 5 ohms, go to next step. 28. Check COIL- For Short To Power Turn ignition on. Measure voltage between J3 (COIL-) and J7 (B -). If DC voltage is less than 5.5 volts, go to next step. If DC voltage is 5.5 volts or more, repair short to power in COIL- circuit between coil and ICM. Coil may also be damaged. 29. Check COIL- For Short To Ground Turn ignition off. Measure resistance between J3 (COIL-) and J7 (B -). If resistance is more than 10,000 ohms, go to next step. If resistance is 10,000 or less, repair short to ground in COIL- circuit between coil and ICM. 30. Check GND At ICM Measure resistance between J9 (GND) and J7 (B -). If resistance is less than 5 ohms, replace ICM. If resistance is 5 ohms or more, go to next step. 31. Check GND At CMP Sensor Connect diagnostic cable between CMP sensor and sensor wiring harness connector. If resistance is less than 5 ohms, repair open in GND circuit between CMP sensor and ICM. If resistance is 5 ohms or more, check ground circuit. If ground circuit is okay, replace CMP sensor. PINPOINT TEST AAA: NO START WITH SPOUT CONNECTOR DISCONNECTED (REMOTE MOUNTED ICM) 1. Check For Codes Perform QUICK TEST. See TESTS W/CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section. If diagnostic trouble codes are present, service codes as required. If codes are not present, go to next step. 2. Check Battery Turn ignition on. Check battery voltage. If battery voltage is less than 12 volts, service battery as necessary. If battery voltage is more than 12 volts, go to next step. 3. Check For PIP Signal Turn ignition off. Connect EEC-IV Diagnostic Cable (007-00097) to EEC- IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. Leave B+ lead of diagnostic cable disconnected. See Fig 4. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is

Page 23 of 34 in NORMAL position. Apply DI overlay on breakout box. Ensure SPOUT in-line connector is disconnected. WARNING: DO NOT connect EEC-IV Diagnostic Cable and PCM to EEC-IV Breakout Box simultaneously. Turn ignition on. Put DVOM on AC voltage scale. Crank engine while measuring voltage between J15 (PIP) and J7 (B -). If AC voltage is 3.0-8.5 volts, replace ICM. If AC voltage is not 3.0-8.5 volts, go to next step. 4) Check PIP Signal From PIP Sensor Connect diagnostic cable to CMP sensor and sensor connector. Turn switch to PIP OPEN position. Crank engine while measuring voltage between J7 (B -) and J41 (PIP B). If AC voltage is 3.0-8.5 volts, repair open in PIP circuit between ICM and CMP sensor. If AC voltage is not 3.0-8.5 volts, check CMP wiring harness connector. Repair as necessary. If connector is okay, replace CMP sensor. PINPOINT TEST B: CONTINUOUS MEMORY CODE 212 1. Connect Test Equipment Turn ignition off. Connect DI Diagnostic Cable (007-00097) to EEC- IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. See Fig 4. Leave B+ lead disconnected. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position. Use DI overlay on breakout box. Disconnect PCM and go to next step. 2. Check IDM Signal At PCM Turn ignition off. Set DVOM on AC scale. Crank engine while measuring voltage between J7 (B -) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If AC voltage is more than 1.0 volt, replace PCM. If AC voltage is 1.0 volt or less, go to next step. 3. Check For Short To Power In IDM Turn ignition off. Disconnect diagnostic connector from ICM. Leave ICM wiring harness connected to diagnostic cable. Set DVOM on DC scale. Turn ignition on. Measure voltage between J7 (B -) and J23 (IDM). If voltage is less than 0.5 volt, go to next step. If voltage is 0.5 volt or more, repair short to power in IDM circuit between PCM and ICM wiring harness connector. 4. Check For Short To Ground In IDM Turn ignition off. Measure resistance between J7 (B -) and J23 (IDM). If resistance is 10,000 ohms or less, repair short to ground in IDM circuit between PCM and ICM wiring harness connector. If resistance is more than 10,000 ohms, go to next step. 5. Check For Open IDM Measure resistance between and J23 (IDM) and terminal No. 4 of PCM wiring harness connector. If resistance is less than 5 ohms, replace ICM. If resistance is 5 ohms or more, repair open in IDM circuit between PCM and ICM wiring harness connector. PINPOINT TEST C KOER CODE 213: TIMING INCORRECT, SPOUT OPEN, POOR FUEL ECONOMY OR POOR DRIVEABILITY 1. Check Base Timing Check ignition timing. See IGNITION TIMING in appropriate ADJUSTMENTS - V8 article in the ENGINE PERFORMANCE section. If ignition timing is within 3 degrees of base timing specification, go to next step. If timing is not within 3 degrees of base timing specification, adjust timing. 2. Check Spark Advance Turn ignition off. Reconnect SPOUT in-line connector. Ensure engine is at normal operating temperature. Start engine and allow it to idle. Check ignition timing. If timing is more than 18 degrees BTDC, problem is not ignition related. See appropriate TESTS W/O

Page 24 of 34 CODES - EEC-IV (5.0L) article in the ENGINE PERFORMANCE section for more symptom diagnosis. If timing is not as specified, go to next step. 3. Check For Good SPOUT To ICM Connect DI Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EEC-IV), negative battery terminal and ICM. See Fig 4. Leave B+ lead disconnected. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in SPOUT OPEN position. Apply DI overlay on breakout box. Set DVOM on AC scale. Start engine and allow to idle. Measure voltage between J7 (B-) and J10 (SPOUT). If AC voltage is 3.0-8.5 volts, replace ICM. If AC voltage is not 3.0-8.5 volts, go to next step. 4. Check For SPOUT Open In Harness Turn ignition off. Disconnect PCM wiring harness connector. Disconnect diagnostic connector from ICM. Leave ICM wiring harness connector connected to diagnostic cable. Measure resistance between J10 (SPOUT) at breakout box and terminal No. 36 (SPOUT) at PCM wiring harness connector. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in SPOUT circuit between PCM and ICM wiring harness connector. EMISSION SYSTEMS & SUB-SYSTEMS SECONDARY AIR INJECTION (AIR) Air Pump Check belt tension, and adjust if necessary. Disconnect air supply hose from Secondary Air Injection By- Pass (AIRB) valve. Start engine. If airflow is felt at pump outlet and increases as engine speed is increased, pump is okay. If airflow is not felt at pump outlet and/or does not increase as engine speed is increased, replace air pump. CAUTION: DO NOT pry on air pump to adjust belt tension. Aluminum housing of pump may collapse. Air Silencer/Filter (Air Pump & Pulse Air Inlet) Inspect hoses and air silencer for leaks. Disconnect hose from air silencer outlet. Remove silencer from vehicle, and visually inspect it for plugging. If no plugging or leaks are found, silencer is okay. If any plugging or leaks are found, repair or replace as necessary. Secondary Air Inj. By-Pass (AIRB) Valve (Normally Closed) 1. Disconnect air supply hose at AIRB valve outlet. See Fig 8. Remove vacuum line from vacuum nipple. Ensure vacuum exists at vacuum line before proceeding.