G - TESTS W/CODES - EEC-IV (4.0L)

Transcription

1 Article Text Monday, November 16, :39AM ARTICLE BEGINNING 1995 ENGINE PERFORMANCE Ford Motor Co. Self-Diagnostics - EEC-IV 4.0L Ford; Aerostar, Explorer INTRODUCTION Perform all steps in F - BASIC TESTING - 4.0L article in the ENGINE PERFORMANCE section. If no fault is found while performing steps in F - BASIC TESTING, proceed with self-diagnostics. If no diagnostic trouble codes or only pass codes (system functioning properly) are found during self-diagnostics, proceed to appropriate H - TESTS W/O CODES (EEC-IV) article in the ENGINE PERFORMANCE section below for diagnosis by symptom. * H - TESTS W/O CODES - EEC-IV (for Aerostar) * H - TESTS W/O CODES - EEC-IV (for Explorer) SELF-DIAGNOSTIC SYSTEM CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION section before disconnecting battery. DIAGNOSTIC FORMATS QUICK TEST and CIRCUIT TESTS are diagnostic formats used to test and service EEC-IV system. QUICK TEST allows technician to identify problems and retrieve diagnostic trouble codes. CIRCUIT TESTS check circuits, sensors and actuators. Before starting any CIRCUIT TEST, follow all steps under QUICK TEST to find correct CIRCUIT TEST. If vehicle passes QUICK TEST and no driveability symptoms or intermittent faults exist, EEC-IV system is okay. DIAGNOSTIC TROUBLE CODES (DTC) During QUICK TEST, 3 types of diagnostic trouble codes are retrieved: KOEO, KOER and Continuous Memory codes. See QUICK TEST for self-test procedures. Codes may be cleared from PCM memory after they have been recorded or repaired. See CLEARING CODES. KOEO & KOER Codes (Hard Faults) These codes indicate faults are present at time of testing. A hard fault may cause CHECK ENGINE light or Malfunction Indicator Light (MIL) to go on and remain on until fault is repaired. If KOEO or KOER codes are retrieved during KOEO SELF-TEST or KOER SELF-TEST, use

2 Article Text (p. 2) Monday, November 16, :39AM DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS to find correct testing and repair procedures. Continuous Memory Codes (Soft Faults) These codes indicate a fault that may or may not be present at time of testing. These codes are used to diagnose intermittent problems. Continuous Memory Codes are retrieved after KOEO SELF-TEST. Some codes may turn on CHECK ENGINE light or Malfunction Indicator Light (MIL). Corresponding soft fault trouble code will be retained in PCM memory. If fault does not reoccur within 40 warm-up cycles (80 cycles on some models), PCM will automatically clear code, or technician may clear codes from memory. See CLEARING CODES. Intermittent faults may be caused by a sensor, connector or wiringrelated problem. See INTERMITTENTS in appropriate H - TESTS W/O CODES (EEC-IV) article in the ENGINE PERFORMANCE section. * H - TESTS W/O CODES - EEC-IV (for Aerostar) * H - TESTS W/O CODES - EEC-IV (for Explorer) CAUTION: Continuous Memory Codes should be recorded when retrieved. These codes may be used to identify intermittent problems that exist after all KOEO and KOER codes have been repaired and a Code 111 (pass code) has been obtained. Some Continuous Memory Code faults may not be valid after KOEO and KOER codes are serviced. RETRIEVING CODES Diagnostic trouble codes are retrieved from EEC-IV system through Data Link Connector (DLC). Various methods and test equipment may be used to access these codes: * Analog Volt-Ohmmeter (VOM). * Scan tester. * Malfunction Indicator Light (MIL)/CHECK ENGINE light. * STAR Series Tester DATA LINK CONNECTOR (DLC) LOCATIONS TABLE Application Location Explorer... Right Rear Of Engine Compartment Aerostar... Left Rear Of Engine Compartment READING CODES KOEO & KOER SELF-TEST Codes PCM outputs codes one digit at a time. These codes indicate current faults in system and should be serviced in order of appearance. Use DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS to identify correct CIRCUIT TEST. If using an analog voltmeter or CHECK ENGINE light or

3 Article Text (p. 3) Monday, November 16, :39AM Malfunction Indicator Light (MIL), pay careful attention to length of pauses in order to read codes correctly. Digits in DTC will be displayed by a needle pulse sweep (analog voltmeter) or a flash (MIL). Diagnostic Trouble Codes (DTC's) are represented by a 3-digit number. For example, the first digit of DTC 312 would be displayed by 3 sweeps/flashes with a 0.4-second pause in-between each sweep/flash. A 2-second pause will occur between first and second digits of DTC. Second digit of DTC 312 will be displayed by one sweep/flash then another 2-second pause. Third digit of DTC 312 will be displayed by 2 sweeps/flashes with a 0.4 pause in-between each sweep/flash. A 4- second pause occurs between each code. See Fig. 1. KOE O codes are separated from Continuous Memory codes by a 6 to 9-second delay, a 0. 4-second sweep/flash (separator pulse) and then another 6 to 9-second delay. See Fig. 2. Scan tester, if used, will count pulses and display them as a digital code. STAR tester cannot be used to read 3-digit codes. Super STAR II or New Generation STAR tester can be used to read 3-digit codes. If using Super STAR II tester, 3-digit codes will only be displayed in fast code mode. If slow code mode is used, display will be blank. Engine Identification (ID) Codes Engine ID codes are issued at beginning of KOER SELF-TEST. Codes are one-digit numbers represented by number of pulses displayed. See Fig. 2. Engine ID code is equal to one-half the number o f engine cylinders. For example, 2 pulses would indicate that engine is a 4- cylinder. Engine ID code is used to verify proper PCM is installed and that SELF-TEST has been entered. Separator Code Single 1/2-second separator pulse is issued 6-9 seconds after last KOEO code. Continuous Memory Codes (intermittent faults) are then displayed 6-9 seconds after 1/2-second separator code. See Fig. 2. Some digital test equipment may display separator code as "10" instead of "1". Pass Codes A Code 111 indicates no diagnostic trouble codes were recorded in that portion of test; system passes that portion of test. If Code 111 is not retrieved in KOEO SELF-TEST, codes retrieved during KOER SELF-TEST may not be valid. Code 111 (pass code) must be obtained in KOEO SELF-TEST. A Code output during KOEO SELF-TEST indicates no KOEO code or Continuous Memory Code was recorded. Continuous Memory Codes Continuous Memory Codes are displayed after separator pulse code in KOEO SELF-TEST. These codes result from information stored by PCM during continuous self-test monitoring. These codes indicate faults recorded within last 40 engine starts (80 engine starts on some models). Fault may or may not be currently present. See DIAGNOSTIC TROUBLE CODE DEFINITION CHARTS. Use these codes for diagnosis only when KOEO SELF-TEST and KOER SELF-TEST result in Code 111.

4 Article Text (p. 4) Monday, November 16, :39AM Fast Codes At start of KOEO SELF-TEST and after Wide Open Throttle (WOT) request in KOER SELF-TEST, PCM outputs short bursts of information, known as FAST CODES, which were used by manufacturer during assembly. These codes contain the identical information as slow codes, but are transmitted at 100 times the normal rate. With most equipment (except Super Star II tester), these code bursts are not visible. An entire code sequence lasts less than 1/2 second. Fig. 1: Reading Diagnostic Trouble Codes Using MIL/CHECK ENGINE Light (Using Analog Voltmeter Is Similar) Courtesy of Ford Motor Co.

5 Article Text (p. 5) Monday, November 16, :39AM Fig. 2: Reading Diagnostic Trouble Codes Courtesy of Ford Motor Co. CLEARING CODES To clear codes from PCM memory, start KOEO SELF-TEST. When diagnostic trouble codes appear on test equipment or Malfunction Indicator Light (MIL), disconnect jumper wire from Self-Test Input (STI) connector. If using STAR Series Tester, unlatch center button. This procedure erases Continuous Memory Codes from PCM memory. If problem has not been corrected or fault is still present, hard code will immediately be reset in PCM memory. CAUTION: DO NOT disconnect vehicle battery to clear codes. This will erase stored operating information from Keep-Alive Memory (KAM). CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION section before disconnecting battery. QUICK TEST Description

6 Article Text (p. 6) Monday, November 16, :39AM Following procedures are functional tests of EEC-IV system. These 5 basic test steps must be followed in sequence to avoid misdiagnosis. * Visual Check * Equipment Hookup * KOEO (Key On Engine Off) SELF-TEST * KOER (Key On Engine Running) SELF-TEST * Continuous Monitor Mode (Wiggle Test) Diagnostic Aids After each service or repair procedure has been completed, repeat QUICK TEST to ensure all EEC-IV systems work properly and diagnostic trouble codes are no longer present. VISUAL CHECK Complete all steps in F - BASIC TESTING - 4.0L article in the ENGINE PERFORMANCE section before proceeding to self-diagnostic tests. Ensure all vacuum hoses and EEC-IV wiring harnesses are properly connected. EQUIPMENT HOOKUP Apply parking brake, and place shift lever in Park (A/T) or Neutral(M/T) position. Block drive wheels. Turn off all electrical accessories. Connect appropriate test equipment to vehicle as follows: Analog Volt-Ohmmeter (VOM) 1) Turn ignition off. Set VOM at 0-15V DC range. Connect positive lead of VOM to positive battery terminal. 2) Connect negative VOM lead to Self-Test Output (STO) terminal of Data Link Connector (DLC). See Fig. 3. Go to KOEO SELF-TEST. Activate KOEO SELF-TEST by connecting jumper wire from Self-Test Input (STI) pigtail to signal return (SIG RTN) terminal at DLC with ignition on. Fig. 3: Self-Test Equipment Hook-Up For Analog VOM (4.0L) Courtesy of Ford Motor Co.

7 Article Text (p. 7) Monday, November 16, :39AM Scan Tester Follow manufacturer's instructions to hook up equipment. Record diagnostic trouble codes. STAR Series Tester Turn ignition off. Connect color-coded adapter cable leads to diagnostic tester. Connect 2 service connectors of adapter cable to vehicle Data Link Connector (DLC) and STI pigtail connector. If using Super STAR II tester, select EEC-IV and Fast modes. On all models, go to KOEO SELF-TEST. CHECK ENGINE Light/Malfunction Indicator Light (MIL) Turn ignition on. Connect a jumper wire between Self-Test Input (STI) pigtail and signal return (SIG RTN) terminal of Data Link Connector (DLC). See Fig. 4. Go to KOEO SELF-TEST. Fig. 4: Self-Test Equipment Hook-Up For CHECK ENGINE Light/ Malfunction Indicator Light (4.0L) Courtesy of Ford Motor Co. KOEO SELF-TEST Ensure engine is warmed to normal operating temperature. If engine does not start (or stalls after starting), continue KOEO SELF- TEST. DO NOT depress throttle. Turn ignition off. Ensure test equipment is properly attached. Turn ignition on (engine off). Record all KOEO and Continuous Memory Codes. If a Code 111 (pass code) is not retrieved, service KOEO codes. See DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS. If PCM will not output codes, go to CIRCUIT TEST QA. If diagnostic trouble codes are retrieved, perform the following: * If MIL/CHECK ENGINE light is on, service diagnostic trouble codes in order retrieved. Proceed to the appropriate

8 Article Text (p. 8) Monday, November 16, :39AM DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS. * If Continuous Memory Code 215, 216, 217, 218, 222, 224, 232 or 238 is retrieved during KOEO SELF-TEST, see IGNITION SYSTEMS in I - SYSTEM/COMPONENT TESTS - EEC-IV (4.0L) article in the ENGINE PERFORMANCE section. * If vehicle has a no-start condition, go to CIRCUIT TEST AA (distributor ignition), or CIRCUIT TEST AC (electronic ignition - high data rate). * If vehicle displays a Code 111 (pass code) and does not have any symptoms described in previous steps, go to KOER SELF -TEST. KOER SELF-TEST Diagnostic Aids DO NOT enter this test sequence until a Code 111 (pass code) has been retrieved in KOEO SELF-TEST. If system has not passed KOEO SELF-TEST, codes recorded in KOER SELF-TEST may not be valid. Deactivate self-test by removing and reconnecting jumper wire or by procedure specified by test equipment in use. Start engine, and run it for 2 minutes at 2000 RPM to warm Heated Exhaust Gas Oxygen Sensor (HO2S). Turn engine off, and wait 10 seconds. Activate KOER SELF-TEST using a jumper wire or appropriate procedure for test equipment used. Start engine. Record all diagnostic trouble codes displayed. Check following items: * If Code 998 is displayed, EEC-IV system is operating in Failure Management Effects Mode (FMEM) and vehicle has not passed KOEO SELF-TEST. Vehicle cannot be diagnosed while in FMEM mode. * If vehicle is equipped with a Brake On-Off (BOO) switch, brake pedal must be depressed and released after ID code portion of test. * On vehicles with Power Steering Pressure (PSP) switch, turn steering wheel at least 1/2 turn and release within 1-2 seconds after ID code portion of test. * If Dynamic Response Code appears, perform a brief Wide Open Throttle (WOT). DO NOT perform WOT unless requested. * If a Code 111 (pass code) is retrieved during KOER SELF-TEST, service Continuous Memory Codes retrieved in KOEO SELF-TEST. See DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS. * If KOER codes are present, see DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS. If system will not output codes, go to CIRCUIT TEST QA. * If a Code 111 (pass code) is retrieved during Continuous Memory Code portion of KOEO SELF-TEST and no driveability problem exists, EEC-IV testing is complete. If driveability problems are still present, go to appropriate H - TESTS W/O CODES - EEC-IV article in the ENGINE PERFORMANCE section below. * H - TESTS W/O CODES - EEC-IV (for Aerostar) * H - TESTS W/O CODES - EEC-IV (for Explorer)

9 Article Text (p. 9) Monday, November 16, :39AM * If a Code 111 (pass code) is retrieved during KOER SELF-TEST and intermittent fault(s) continue, go to CONTINUOUS MONITOR MODE (WIGGLE TEST) below. CONTINUOUS MONITOR MODE (WIGGLE TEST) Continuous Monitor Mode allows technician to attempt to recreate an intermittent fault while monitoring system. This mode, also called wiggle test, may be used in both KOEO SELF-TEST and KOER SELF-TEST. CIRCUIT TESTS specify use of this procedure to identify intermittent faults in specific circuits or components. KOEO Wiggle Test Procedure Connect test equipment. See Fig. 3 or 4. Turn ignition on. Activate self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test. Wiggle test mode is now activated. Tap, move and wiggle suspect sensor and/or harness area. If a fault is detected, a diagnostic trouble code may be stored in memory and indicated at diagnostic tester or scan tester. Retrieve code, and perform appropriate test. See DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS. KOER Wiggle Test Procedure Connect test equipment. See Fig. 3 or 4. Start engine. Activate e self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test. DO NOT turn engine off. KOER wiggle test mode is now activated. Tap, move and wiggle suspect sensor and/or harness area. If a fault is detected, a diagnostic trouble code may be stored in memory and indicated at diagnostic tester or scan tester. Retrieve code, and perform appropriate test. See DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS. ADDITIONAL SYSTEM FUNCTIONS Additional diagnostic system features are available to help diagnose driveability problems and service EEC-IV systems. MALFUNCTION INDICATOR LIGHT (MIL) MIL is intended to alert driver of certain malfunctions in EEC-IV system. Light may also be used to retrieve diagnostic trouble codes stored in PCM. When hooked up for KOEO SELF-TEST or KOER SELF- TEST, light will display all codes which turn on light during vehicle operation. Light should come on when ignition is turned on and go out when engine is started. If light comes on and then goes off during vehicle operation, code causing light to come on will be stored in PCM memory as a Continuous Memory Code. If light comes on during vehicle operation, vehicle should be inspected as soon as possible. Immediately turning off engine is not necessary; vehicle can be driven with light on.

10 Article Text (p. 10) Monday, November 16, :39AM OUTPUT STATE DIAGNOSTIC TEST MODE (DTM) 1) Output state DTM is used as an aid in servicing output actuators associated with EEC-IV system. It allows technicians to energize and de-energize most system output actuators on command. This mode is entered from KOEO SELF-TEST after all codes have been retrieved. 2) Disconnect cruise control servo (if equipped). With DVOM on 20-volt scale, connect DVOM negative lead to STO terminal at Diagnostic Link Connector (DLC). Connect positive lead to positive battery terminal. Using jumper wire, connect STI to SIG RTN at Diagnostic Link Connector (DLC). 3) Perform KOEO SELF-TEST until continuous memory test is complete. DVOM will read less than one volt when test is complete. Depress and release throttle. If voltage increases, output state DTM has been entered. If voltage does not increase, depress throttle to WOT and release. If STO voltage still does not increase, go to CIRCUIT TEST QC. FAILURE MODE EFFECTS MANAGEMENT (FMEM) CODE 998 FMEM mode allows system operation when sensors fail or transmit signals that are out of normal operating range. During FMEM mode, PCM substitutes a mid-range signal for defective sensor while continuing to monitor sensor. If faulty sensor's signals return to normal operating range, PCM will use those signals. A Code 998 will be displayed when FMEM mode is in effect. HARDWARE LIMITED OPERATIONAL STRATEGY (HLOS) HLOS mode is used when system fault(s) is too extreme for Failure Mode Effects Management (FMEM) mode to handle. If a number of system or sensor failures are present and PCM is not receiving enough information to operate, PCM will switch to HLOS mode. PCM will output fixed values to allow operation of vehicle. Driveability concerns will be present. PCM will not output diagnostic trouble codes in this mode. CYLINDER BALANCE TEST This test helps identify a weak or non-contributing cylinder in engines with SFI fuel systems. PCM shuts off fuel supply to each injector and measures RPM drop. It computes variation between cylinders and identifies weak ones. This test mode is entered from KOER SELF-TEST after all codes have been displayed. Within 2 minutes after codes have been displayed, lightly depress throttle (a 2-3 degree throttle angle is required, not a wide open throttle). After a brief stabilizing period, PCM will activate test procedure. Test will be repeated if throttle is depressed within 2 minutes of final code output. During second and third test sequences, percentage of allowable variation between cylinders is reduced. Service codes displayed during this test identify weak or non-

11 Article Text (p. 11) Monday, November 16, :39AM contributing cylinder. See CYLINDER BALANCE TEST DIAGNOSTIC TROUBLE CODES table. If Code 90 is displayed during this test, system has passed test. If Code 77 is displayed, repeat cylinder balance test. If throttle is moved during this test, Code 77 will appear, indicating test is not complete. Repeat cylinder balance test. Total test time is about 3 minutes. CYLINDER BALANCE TEST DIAGNOSTIC TROUBLE CODES TABLE Code Application Pass Cylinder No Cylinder No Cylinder No Cylinder No Cylinder No Cylinder No Cylinder No Cylinder No Retest DIAGNOSTIC TROUBLE CODE DEFINITION CHARTS

12 Article Text (p. 12) Monday, November 16, :39AM Fig. 5: Diagnostic Trouble Code Definition Chart (1 Of 2) Courtesy of Ford Motor Co.

13 Article Text (p. 13) Monday, November 16, :39AM Fig. 6: Diagnostic Trouble Code Definition Chart (2 Of 2) Courtesy of Ford Motor Co.

14 Article Text (p. 14) Monday, November 16, :39AM Fig. 7: Diagnostic Trouble Code Definition Chart (3 Of 2) Courtesy of Ford Motor Co. DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS DTC REFERENCE CHART TABLE 1 (CODE ) ˆ DIAGNOSTIC TROUBLE CODES (DTC) ˆ Go To Circuit Test: ˆ ˆ ˆ Code Application ˆ KOEO ˆ KOER ˆ CONT ˆ š š š ˆ No Codes ˆ All Models ˆ QA1 ˆ QA1 ˆ QA1 ˆ ˆ 111 ˆ All Models ˆ Pass ˆ Pass ˆ Pass ˆ ˆ 112 ˆ All Models ˆ DA20 ˆ ˆ DA90 ˆ ˆ 113 ˆ All Models ˆ DA10 ˆ ˆ DA90 ˆ ˆ 114 ˆ All Models ˆ DA1 ˆ DA1 ˆ ˆ ˆ 116 ˆ All Models ˆ DA1 ˆ DA1 ˆ ˆ ˆ 117 ˆ All Models ˆ DA20 ˆ ˆ DA90 ˆ

15 Article Text (p. 15) Monday, November 16, :39AM ˆ 118 ˆ All Models ˆ DA10 ˆ ˆ DA90 ˆ ˆ 121 ˆ All Models ˆ DH2 ˆ DH1 ˆ G1 ˆ ˆ 122 ˆ All Models ˆ DH10 ˆ ˆ DH94 ˆ ˆ 123 ˆ All Models ˆ DH3 ˆ ˆ DH90 ˆ ˆ 124 ˆ All Models ˆ ˆ ˆ G1 ˆ ˆ 125 ˆ All Models ˆ ˆ ˆ G1 ˆ ˆ 126 ˆ All Models ˆ DF1 ˆ DF1 ˆ DF90 ˆ ˆ 128 ˆ All Models ˆ ˆ ˆ DF11 ˆ ˆ 129 ˆ Models With MAF Sensor ˆ ˆ DC13 ˆ ˆ ˆ ˆ All Other Models ˆ ˆ DF10 ˆ ˆ ˆ 136 ˆ All Models ˆ ˆ H1 ˆ ˆ ˆ 137 ˆ All Models ˆ ˆ H1 ˆ ˆ ˆ 139 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 141 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 144 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 157 ˆ All Models ˆ ˆ ˆ DC10 ˆ ˆ 158 ˆ All Models ˆ DC22 ˆ ˆ DC22 ˆ ˆ 159 ˆ All Models ˆ DC1 ˆ DC1 ˆ ˆ ˆ 167 ˆ All Models ˆ ˆ DH20 ˆ ˆ ˆ 171 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 172 ˆ All Models ˆ ˆ H1 ˆ H1 ˆ ˆ 173 ˆ All Models ˆ ˆ H1 ˆ H1 ˆ ˆ 174 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 175 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 176 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 177 ˆ All Models ˆ ˆ ˆ H1 ˆ ˆ 178 ˆ All Models ˆ ˆ ˆ H1 ˆ

16 Article Text (p. 16) Monday, November 16, :39AM ˆ 179 ˆ All Models ˆ ˆ ˆ HA1 ˆ ˆ 181 ˆ All Models ˆ ˆ ˆ HA1 ˆ ˆ 184 ˆ All Models ˆ ˆ ˆ G7 ˆ ˆ 185 ˆ All Models ˆ ˆ ˆ G7 ˆ ˆ 186 ˆ All Models ˆ ˆ ˆ G9 ˆ ˆ 187 ˆ All Models ˆ ˆ ˆ G7 ˆ ˆ 188 ˆ All Models ˆ ˆ ˆ HA1 ˆ DTC REFERENCE CHART TABLE 2 (CODE ) ˆ DIAGNOSTIC TROUBLE CODES (DTC) ˆ Go To Circuit Test: ˆ ˆ ˆ Code Application ˆ KOEO ˆ KOER ˆ CONT ˆ š š š ˆ 189 ˆ All Models ˆ ˆ ˆ HA1 ˆ ˆ 193 ˆ All Models ˆ DE1 ˆ ˆ ˆ ˆ 194 ˆ All Models ˆ ˆ ˆ HA5 ˆ ˆ 195 ˆ All Models ˆ ˆ ˆ HA5 ˆ ˆ 211 ˆ 4.0L ˆ ˆ ˆ NC1 ˆ ˆ 212 ˆ 4.0L ˆ ˆ ˆ NC3 ˆ ˆ 213 ˆ 4.0L ˆ ˆ PC1 ˆ ˆ ˆ 214 ˆ All Models ˆ ˆ ˆ DR1 ˆ ˆ 215 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 216 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 217 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 218 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 219 ˆ All Models ˆ ˆ ˆ PB10 ˆ ˆ 222 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 224 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 225 ˆ All Models ˆ ˆ DG1 ˆ ˆ

17 Article Text (p. 17) ˆ 226 ˆ All Models ˆ NC2 ˆ ˆ ˆ ˆ 232 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 238 ˆ All Models ˆ ˆ ˆ (1) ˆ ˆ 244 ˆ All Models ˆ ˆ DR1 ˆ ˆ ˆ 311 ˆ All Models ˆ ˆ KC1 ˆ ˆ ˆ 312 ˆ All Models ˆ ˆ KC1 ˆ ˆ ˆ 313 ˆ All Models ˆ ˆ KC1 ˆ ˆ ˆ 314 ˆ All Models ˆ ˆ KC1 ˆ ˆ ˆ 326 ˆ All Models ˆ ˆ DL22 ˆ ˆ ˆ 327 ˆ DPFE - 4.0L Explorer ˆ DL1 ˆ DL22 ˆ DL90 ˆ ˆ 328 ˆ All Models ˆ DN25 ˆ DN25 ˆ DN90 ˆ ˆ 332 ˆ DPFE - 4.0L Explorer ˆ ˆ DL30 ˆ DL90 ˆ ˆ 334 ˆ All Models ˆ DN20 ˆ DN20 ˆDN115 ˆ ˆ 335 ˆ All Models ˆ DL80 ˆ ˆ ˆ ˆ 336 ˆ DPFE - 4.0L Explorer ˆ ˆ DL50 ˆ DL90 ˆ ˆ 337 ˆ DPFE - 4.0L Explorer ˆ DL5 ˆ DL50 ˆ DL90 ˆ ˆ(1) - Refer to I - SYSTEM/COMPONENT TESTS - EEC-IV (4.0L) ˆ ˆ article. ˆ DTC REFERENCE CHART TABLE 3 (CODE ) ˆ DIAGNOSTIC TROUBLE CODES (DTC) ˆ Go To Circuit Test: ˆ ˆ ˆ Code Application ˆ KOEO ˆ KOER ˆ CONT ˆ š š š ˆ 338 ˆ All Models ˆ ˆ ˆDA100 ˆ ˆ 339 ˆ All Models ˆ ˆ ˆDA101 ˆ ˆ 341 ˆ All Models ˆ KP1 ˆ ˆ ˆ ˆ 411 ˆ All Models ˆ ˆ KE15 ˆ ˆ ˆ 412 ˆ All Models ˆ ˆ KE1 ˆ ˆ ˆ 452 ˆ Aerostar ˆ ˆ ˆ DS1 ˆ

18 Article Text (p. 18) ˆ ˆ Explorer ˆ ˆ ˆ DP1 ˆ š š ˆ 511 ˆ All Models ˆ Replace PCM ˆ š š ˆ 512 ˆ All Models ˆ ˆ ˆ QB1 ˆ ˆ 513 ˆ All Models ˆ QD1 ˆ QD1 ˆ QD1 ˆ ˆ 519 ˆ All Models ˆ FF1 ˆ ˆ ˆ ˆ 521 ˆ All Models ˆ ˆ FF5 ˆ ˆ ˆ 522 ˆ Aerostar ˆ TD1 ˆ ˆ ˆ ˆ ˆ Explorer ˆ TA1 ˆ ˆ ˆ ˆ 525 ˆ All Models ˆ TA1 ˆ ˆ TA1 ˆ ˆ 528 ˆ All Models ˆ ˆ ˆ TA1 ˆ ˆ 542 ˆ All Models ˆ J10 ˆ ˆ J90 ˆ ˆ 543 ˆ All Models ˆ J20 ˆ ˆ J93 ˆ ˆ 551 ˆ All Models ˆ KT1 ˆ ˆ ˆ ˆ 552 ˆ All Models ˆ KC9 ˆ ˆ ˆ ˆ 553 ˆ All Models ˆ KC9 ˆ ˆ ˆ ˆ 554 ˆ All Models ˆ KN1 ˆ ˆ ˆ ˆ 556 ˆ All Models ˆ J1 ˆ ˆ ˆ ˆ 558 ˆ DPFE - 4.0L Explorer ˆ DL10 ˆ DL5 ˆ DN90 ˆ ˆ 559 ˆ All Models ˆ KM60 ˆ ˆ ˆ ˆ 565 ˆ Explorer ˆ KB1 ˆ ˆ ˆ ˆ ˆ Aerostar ˆ KD6 ˆ ˆ ˆ ˆ 566 ˆ All Models ˆ TC1 ˆ ˆ ˆ ˆ 569 ˆ All Models ˆ KD6 ˆ ˆ ˆ ˆ 617 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 618 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 619 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 621 ˆ All Models ˆ TC1 ˆ ˆ ˆ

19 Article Text (p. 19) DTC REFERENCE CHART TABLE 3 (CODE ) ˆ DIAGNOSTIC TROUBLE CODES (DTC) ˆ Go To Circuit Test: ˆ ˆ ˆ Code Application ˆ KOEO ˆ KOER ˆ CONT ˆ š š š ˆ 622 ˆ All Models ˆ TC1 ˆ ˆ ˆ ˆ 623 ˆ All Models ˆ TB3 ˆ ˆ ˆ ˆ 624 ˆ All Models ˆ TC10 ˆ ˆ TG90 ˆ ˆ 625 ˆ All Models ˆ TC10 ˆ ˆ TG90 ˆ ˆ 626 ˆ All Models ˆ TC1 ˆ ˆ ˆ ˆ 627 ˆ All Models ˆ TC1 ˆ ˆ ˆ ˆ 628 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 629 ˆ All Models ˆ TC1 ˆ ˆ TG90 ˆ ˆ 631 ˆ All Models ˆ TB3 ˆ ˆ ˆ ˆ 632 ˆ All Models ˆ ˆ TB2 ˆ NA2 ˆ ˆ 633 ˆ All Models ˆ TB1 ˆ ˆ ˆ ˆ 634 ˆ All Models ˆ TD1 ˆ ˆ TG90 ˆ ˆ 636 ˆ All Models ˆ TE1 ˆ TE1 ˆ ˆ ˆ 637 ˆ All Models ˆ TE10 ˆ ˆ TE90 ˆ ˆ 638 ˆ All Models ˆ TE20 ˆ ˆ TE90 ˆ ˆ 639 ˆ All Models ˆ ˆ TF1 ˆ TF90 ˆ ˆ 641 ˆ All Models ˆ TC1 ˆ ˆ ˆ ˆ 643 ˆ All Models ˆ TC20 ˆ ˆ TC30 ˆ ˆ 645 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 646 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 647 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 648 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 649 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 651 ˆ All Models ˆ ˆ ˆ TG90 ˆ

20 Article Text (p. 20) ˆ 652 ˆ All Models ˆ TC1 ˆ ˆ ˆ ˆ 653 ˆ All Models ˆ ˆ TB2 ˆ ˆ ˆ 654 ˆ All Models ˆ TD1 ˆ ˆ ˆ ˆ 656 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 657 ˆ All Models ˆ ˆ ˆTE100 ˆ ˆ 659 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 667 ˆ All Models ˆ TD1 ˆ TD1 ˆ TG90 ˆ ˆ 675 ˆ All Models ˆ ˆ ˆ TG90 ˆ ˆ 676 ˆ All Models ˆ (1) ˆ (1) ˆ (1) ˆ ˆ 677 ˆ All Models ˆ (1) ˆ (1) ˆ (1) ˆ ˆ 691 ˆ All Models ˆ ˆ ˆ TB1 ˆ ˆ 692 ˆ All Models ˆ (1) ˆ (1) ˆ (1) ˆ ˆ 998 ˆ All Models ˆ FMEM ˆ ˆ ˆ ˆ Code Not ˆ All Models ˆ QA1 ˆ QA1 ˆ QA1 ˆ ˆ Listed ˆ ˆ ˆ ˆ ˆ ˆ(1) - Check transmission for mechanical problem. ˆ CIRCUIT TESTS NOTE: A breakout box, connected to vehicle harness at PCM, is necessary to perform most circuit tests. References to Test Pin No. found in CIRCUIT TEST steps refer to test terminals on manufacturer breakout box overlay. Circuit diagrams at beginning of each test identify circuit and wire colors. HOW TO USE CIRCUIT TESTS 1) Ensure all non-eec-iv related faults found while performing steps in F - BASIC TESTING - 4.0L article in the ENGINE PERFORMANCE section have been corrected. Follow each test step in order until fault is found. When more than one code is retrieved, start with first code displayed. 2) CIRCUIT TESTS ensure electrical circuits are okay before sensors or other components are replaced. Always test circuits for continuity between sensor and PCM. Test all circuits for short to power, open or short to ground. Voltage Reference (VREF) and Voltage

21 Article Text (p. 21) Power (VPWR) circuits should be tested with ignition on unless otherwise specified in CIRCUIT TESTS. 3) DO NOT measure voltage or resistance at PCM. DO NOT connect any test light unless specified in testing procedure. All measurements are made by probing rear of connector. Isolate both ends of a circuit and turn ignition off when checking continuity. 4) Disconnect solenoids and switches from harness before measuring continuity and resistance or applying voltage. After each repair, reconnect all component connections and repeat QUICK TEST. 5) An open circuit is defined as a resistance reading of greater than 5 ohms. This specification tolerance may be too high for some items in EEC-IV system. If resistance approaches 5 ohms, always clean suspect connector and coat it with protective dielectric silicone grease. A short to ground is defined as a resistance reading of less than 10,000 ohms, unless stated otherwise in CIRCUIT TEST. NOTE: In following tests, circuit diagrams and illustrations are courtesy of Ford Motor Co. CIRCUIT TESTS are grouped as follows. * AA-C - No Start & Voltage Tests. * DA-DS - Input Sensor Tests. * FD-FF - Additional Input Component Tests. * G-J - Fuel Control Systems. * KB-TG - PCM Output Tests CIRCUIT TEST AA - NO START (DISTRIBUTOR IGNITION SYSTEMS) CAUTION: Stop this test at first sign of a fuel leak. DO NOT allow smoking or an open flame in vicinity of vehicle during these tests. Diagnostic Aids Enter this CIRCUIT TEST only when steps in QUICK TEST have been successfully completed but engine still does not start or if directed here from another test or chart. This test is only intended to diagnose the following EEC-IV ignition systems and circuits: * Powertrain Control Module (PCM). * Spark (PCM-controlled). * Wiring harness circuits (PIP, SPOUT, IGN GND and VPWR). TEST PIN NO. 16 (IGN GND) WIRE COLOR IDENTIFICATION TABLE Application Wire Color All Models... Orange/Red TEST PIN NO. 36 (SPOUT) WIRE COLOR IDENTIFICATION TABLE

22 Article Text (p. 22) Application Wire Color All Models... Pink TEST PIN NO. 56 (PIP) WIRE COLOR IDENTIFICATION TABLE Application Wire Color All Models... Gray/Orange Fig. 8: ICM Circuit & Connector Terminal ID (4.0L) To prevent replacement of good components, be aware the following non-eec related areas and components may be cause of problem: * Fuel quality and quantity. * Ignition (general system condition). * Engine mechanical components. * Starter and battery circuits. * Distributor. * Camshaft Position (CMP) sensor. * Ignition Control Module (ICM). * Ignition coil. 1) Check No-Start Condition Try to start engine. If engine does not start, go to next step. If engine starts, no-start condition is intermittent. Check and repair ignition system as necessary. Proceed to appropriate I - SYSTEM/COMPONENT TESTS - EEC-IV (4.0L) article in the ENGINE PERFORMANCE section. 2) Attempt To Crank Engine Try to crank engine. If engine does not crank, check vehicle starting and charging systems. If engine cranks, verify inertia switch

23 Article Text (p. 23) button is pushed in. If inertia switch button is pushed in, go to next step. 3) Check VREF Signal At TP Sensor Turn ignition off. Disconnect Throttle Position (TP) sensor. Turn ignition on (engine off). Measure voltage at TP sensor harness connector between VREF and SIG RTN. See Fig. 9. If voltage is 4-6 volts, reconnect TP sensor and go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C. Fig. 9: TP Sensor Wiring Harness Connector Terminal ID (4.0L) 4) Check For Spark At Plugs Disconnect any spark plug wire. Connect spark tester between spark plug wire and ground. Crank engine and check for spark. If spark is present and consistent, connect spark plug wire and go to step 14). If spark does not exist, connect spark plug wire and go to step next step. 5) Check For Spark At Coil Remove coil secondary wire from distributor. Install spark tester. Check for spark while cranking engine. If spark exists, connect coil wire, and service ignition secondary system. If no spark exists, connect coil wire and go to next step. 6) Check Ignition Circuit Ground Continuity

24 Article Text (p. 24) Turn ignition off. Disconnect and inspect PCM 60-pin connector. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect Camshaft Position (CMP) sensor connector. Measure resistance between test pin No. 16 at breakout box and IGN GND circuit of CMP sensor connector. If resistance is 5 ohms or more, repair open IGN GND circuit. Remove breakout box, reconnect components and repeat QUICK TEST. If resistance is less than 5 ohms, go to next step. 7) Isolate SPOUT Circuit Fault Connect CMP sensor connector. Connect PCM to breakout box. Set breakout box timing switch to DIST position. Try to start vehicle. If vehicle starts, go to step 12). If vehicle does not start, go to next step. 8) Check SPOUT Signal Turn ignition off. Set breakout box timing switch to DIST position. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between test pin No. 36 at breakout box and negative battery terminal while cranking engine. If voltage is 3-6 volts, EEC-IV system is not at fault. Diagnose ignition system. See IGNITION SYSTEMS in I - SYSTEM/COMPONENT TESTS - EEC-IV (4.0L) article in the ENGINE PERFORMANCE section. If voltage is not 3-6 volts, go to next step. 9) Check SPOUT & PIP Circuits For Short To Power Turn ignition off. With breakout box installed, move timing switch to COMPUTED position. Disconnect PCM. Disconnect CMP sensor and ICM connectors. Turn ignition on. Measure voltage between test pin No. 36 (SPOUT) and negative battery terminal. Also, measure voltage between test pin No. 56 (PIP) and negative battery terminal. If either reading is more than 10.5 volts, repair short to power. Remove breakout box, reconnect components and repeat QUICK TEST. If both readings are 10.5 volts or less, go to next step. 10) Check SPOUT & PIP Circuits For Short To Ground Turn ignition off. Measure resistance between test pin No. 36 (SPOUT) and test pins No. 16, 20, 40, 46 and 60 for short to ground. Also, measure resistance between test pin No. 36 and test pin No. 56 for short to PIP. Also, measure resistance between test pin No. 56 (PIP) and test pins No. 16, 20, 40, 46 and 60. If all readings are 10, 000 ohms or more, go to next step. If any reading is less than 10,000 ohms, repair short in wiring harness. Remove breakout box, reconnect components and repeat QUICK TEST. If engine still does not start, go to next step. 11) Isolate Shorts In PCM Turn ignition off. With breakout box installed, reconnect PCM. Disconnect CMP and ICM connectors. Measure resistance between test pin No. 36 (SPOUT) and test pins No. 37, 40, 57 and 60. Measure resistance between test pin No. 56 (PIP) and test pins No. 37, 40, 57 and 60. If any reading is less than 500 ohms, replace PCM. Remove breakout box, reconnect components and repeat QUICK TEST. If all readings are 500 ohms or more, reconnect components, and go to next step. 12) Check PIP Signal Turn ignition off. With breakout box installed and PCM connected, move timing switch to COMPUTED position. While cranking engine, measure voltage between test pin No. 56 (PIP) and test pins

25 Article Text (p. 25) No. 40 and 60. If voltage is 3-7 volts, replace PCM. Remove breakout box, reconnect components and repeat QUICK TEST. If voltage is not 3-7 volts, go to next step. 13) Check Continuity Of PIP Circuit Turn ignition off. Disconnect PCM from breakout box. Disconnect CMP sensor and ICM connectors. Measure resistance between test pin No. 56 and PIP circuit of ICM or CMP sensor. If resistance is 5 ohms or more, repair open PIP circuit. Remove breakout box, reconnect components and repeat QUICK TEST. If resistance is less than 5 ohms, remove breakout box and diagnose ignition system. See IGNITION SYSTEM in I - SYSTEM/COMPONENT TESTS - EEC-IV (4.0L) article in the ENGINE PERFORMANCE section. 14) Verify SPOUT Signal Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install breakout box, leaving PCM connected. Ensure breakout box timing switch is in COMPUTED position. Set DVOM on 20- volt scale. Measure voltage between test pin No. 36 and test pins No. 40 and 60 while cranking engine. If voltage is 3-6 volts, go to step 21). If voltage is not 3-6 volts, return to step 9). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 14) to step 21). No test procedures have been omitted. CAUTION: Use safety precautions when working on fuel system. DO NOT allow smoking or open flame. If fuel starts leaking, immediately turn ignition off. 21) Fuel Pump Check Connect pressure gauge to vehicle. Note initial pressure reading. Pressurize fuel system by turning ignition on for one second, and observe pressure gauge. Turn ignition off, and wait 10 seconds. Repeat sequence 5 times. If pressure increases, go to CIRCUIT TEST S. If pressure does not increase, repair fuel system as necessary. See FUEL SYSTEM in F - BASIC TESTING - 4.0L article in the ENGINE PERFORMANCE section. CIRCUIT TEST AC - NO START (4.0L) CAUTION: Stop this test at first sign of a fuel leak. DO NOT allow smoking or an open flame in vicinity of vehicle during these tests. Diagnostic Aids Enter this CIRCUIT TEST only when all steps under QUICK TEST have been successfully completed and engine still does not start or if directed here from another test or chart. This test is only intended to diagnose: * Spark (PCM-controlled). * Wiring harness circuits (PIP, IGN GND and VPWR). * Powertrain Control Module (PCM).

26 Article Text (p. 26) To prevent replacement of good components, be aware the following non-eec related areas and components may be cause of problem: * Fuel quality and quantity. * Ignition (general condition). * Engine mechanical components. * Starter and battery circuits. * Crankshaft Position (CKP) sensor. * Ignition Control Module (ICM). * Coil packs. Fig. 10: Ignition System Wiring Diagram (4.0L) TEST PIN NO. 4 (IDM) WIRE COLOR IDENTIFICATION TABLE Application Wire Color

27 Article Text (p. 27) 4.0L... Tan/Yellow TEST PIN NO. 36 (SPOUT) WIRE COLOR IDENTIFICATION TABLE Application Wire Color 4.0L... Pink TEST PIN NO. 56 (PIP) WIRE COLOR IDENTIFICATION TABLE Application Wire Color 4.0L... Gray/Orange 1) Starting System Ensure fuel pump Inertia Fuel Shutoff (IFS) switch is closed (button pushed in). Try to start engine. If engine does not crank, check vehicle starting and charging systems. If engine cranks, go to step 2). 2) Check VREF Signal At TP Sensor Turn ignition off. Disconnect Throttle Position (TP) sensor. Turn ignition on (engine off). Measure voltage between VREF and SIG RTN at TP sensor harness connector.see Fig. 11. If voltage is not 4-6 volts, go to CIRCUIT TEST C. If voltage is 4-6 volts, reconnect TP sensor and go to next step. Fig. 11: TP Sensor Wiring Harness Connector Terminal ID (4.0L) 3) Check For Spark At Plugs Disconnect any spark plug wire. Connect spark tester between plug wire and engine ground. Crank engine and check for spark. If

28 Article Text (p. 28) spark is present, reconnect spark plug wire and go to next step. If spark is not present, check ignition system. See IGNITION SYSTEMS in I - SYSTEM/COMPONENT TESTS - EEC-IV (4.0L) article in the ENGINE PERFORMANCE section. 4) Check IGN GND Continuity Turn ignition off, and wait 10 seconds. Disconnect PCM 60-pin connector and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect Ignition Control Module (ICM). Measure resistance between test pin No. 16 breakout box and IGN GND terminal at ICM wiring harness connector. If resistance is 5 ohms or more, repair open IGN GND circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step. 5) Check PIP For Short To Power Ensure ICM and PCM are disconnected. Turn ignition on. Measure voltage between test pin No. 56 at breakout box and negative battery terminal. If voltage is greater than 7 volts, repair PIP circuit for short to power, and repeat QUICK TEST. If voltage is 7 volts or less, go to next step. 6) Check PIP Circuit Continuity Turn ignition off. Measure resistance between test pin No. 56 at breakout box and PIP terminal at ICM wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open PIP circuit and repeat QUICK TEST. 7) Check PIP Circuit For Short To Ground Ensure ICM and PCM are disconnected. Measure resistance between test pin No. 56 (PIP) and test pins No. 16, 40, 46 and 60 for short to ground. If any reading is less than 10,000 ohms, repair shorted PIP circuit and repeat QUICK TEST. If engine still does not start, go to next step. If all readings are 10,000 ohms or more, go to next step. 8) Isolate Shorts In PCM Ensure ignition is turned off. With breakout box installed, connect PCM to breakout box. Leave ICM disconnected. Measure resistance between test pin No. 56 (PIP) and test pins No. 37 and 57 for short to power. Measure resistance between test pin No. 56 and test pins No. 40 and 60 for short to ground. If any reading is not 15, ,000 ohms, replace PCM and repeat QUICK TEST. If all readings are 15, ,000 ohms, go to next step. 9) Check PIP Signal Turn ignition off. Disconnect PCM from breakout box. Reconnect ICM wiring harness connector. Measure voltage between test pins No. 56 and 16 at breakout box while cranking engine. Record voltage. If voltage is 3-7 volts, go to next step. If voltage is not 3-7 volts, replace ICM and repeat QUICK TEST. 10) Isolate Short In PCM Turn ignition off. Reconnect PCM to breakout box, leaving ICM disconnected. Measure voltage between test pins No. 56 and 16 at breakout box while cranking engine. Record voltage. If voltage is 3-7 volts, go to next step. If voltage is not 3-7 volts, replace PCM and repeat QUICK TEST. CAUTION: Stop this test at first sign of a fuel leak. DO NOT allow

29 Article Text (p. 29) smoking or an open flame in vicinity of vehicle during these tests. 11) Fuel Pump Check Connect fuel pressure gauge to vehicle. Note initial fuel pressure reading. Pressurize fuel system by turning ignition on for one second, and observe pressure gauge. Turn ignition off, and wait 10 seconds. Repeat sequence 5 times. If pressure increases, go to CIRCUIT TEST S. If pressure does not increase, go to FUEL SYSTEM in I - SYSTEM/COMPONENT TESTS - EEC-IV (4.0L) article in the ENGINE PERFORMANCE section. CIRCUIT TEST B - CHECKING VEHICLE BATTERY Diagnostic Aids Enter this CIRCUIT TEST only when directed by CIRCUIT TEST C, CIRCUIT TEST J, CIRCUIT TEST PA or CIRCUIT TEST PC. This test is only intended to diagnose following: * Power Control Module (PCM). * EEC power relay. * Ignition switch. * Wiring harness circuits (SIG RTN, PWR GND, VPWR, KAPWR and VREF). To prevent replacement of good components, be aware the following non-eec related areas and components may be cause of problem: * Battery cables and ground straps. * Voltage regulator. * Alternator. * Ignition switch. Fig. 12: Identifying Power Relay Circuits (Aerostar)

30 Article Text (p. 30) Fig. 13: Identifying Power Relay Circuits (Explorer) CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION section before disconnecting battery. 1) Battery Voltage Check Turn ignition on (engine off). Measure battery voltage. If voltage is less than 10.5 volts, recharge or replace battery. If voltage is 10.5 volts or more, go to next step. 2) Check Continuity Of PWR GND Circuit Turn ignition off. Wait 10 seconds. Disconnect PCM. Inspect connector pins and repair if necessary. Install Breakout Box (T83L-50- EEC-IV), leaving PCM connected. Measure resistance between test pins No. 40 and 60 at breakout box and negative battery terminal. If resistance is 5 ohms or more, repair open PWR GND circuit, and repeat QUICK TEST. If both readings are less than 5 ohms, go to next step. 3) Check For Open Between SIG RTN & PWR GND Circuits At PCM - With breakout box installed and PCM connected, measure resistance between test pin No. 46 and test pins No. 40 and 60 at breakout box. If readings are 5 ohms or more, replace PCM and repeat QUICK TEST. If resistance readings are less than 5 ohms, go to next step. 4) Check Continuity Of SIG RTN Circuit Ensure ignition is turned off. Measure resistance between test pin No. 46 at breakout box and SIG RTN terminal of Data Link Connector (DLC). If resistance is 5 ohms or more, repair open SIG RTN circuit and repeat QUICK TEST. If resistance is less than 5 ohms, go to next step. 5) Check KAPWR Circuit Voltage At EEC Power Relay Turn ignition off. Locate relay block in engine compartment. Disconnect EEC power relay from relay block. Turn ignition on. Measure

31 Article Text (p. 31) voltage between KAPWR terminal at EEC power relay connector and negative battery terminal. Measure voltage between test pin No. 1 at breakout box and negative battery terminal. If either voltage is 10.5 volts or less, repair open KAPWR circuit between EEC power relay and positive battery terminal. If voltage is 10.5 volts or more, go to next step. NOTE: Vehicles equipped with Power Distribution Boxes use a diode to provide electrical surge protection for the ignition switch and Ignition Control Module (ICM). If a no-start/no-code condition exists, ensure diode continuity is present in one direction only before going to step 6). 6) Check Ignition Circuit Voltage At EEC Power Relay Ensure PCM is connected to breakout box and EEC power relay is disconnected. Turn ignition on. Measure voltage between negative battery terminal and IGNITION terminal at EEC power relay connector. If voltage is less than 10.5 volts, repair open ignition switch circuit and repeat QUICK TEST. If voltage is 10.5 volts or more, go to next step. 7) Check PWR GND Circuit Continuity Turn ignition off, and wait 10 seconds. With PCM connected to breakout box, measure resistance between negative battery terminal and PWR GND terminal at EEC power relay connector. If resistance is 10 ohms or more, repair open circuit and repeat QUICK TEST. If reading is less than 10 ohms, go to next step. 8) Check VPWR Circuit Continuity Turn ignition off. Measure resistance between test pins No. 37 and 57 (VPWR) at breakout box and VPWR terminal of EEC power relay connector. If resistance is 5 ohms or more, repair open VPWR circuit between EEC power relay and PCM. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step. 9) Check VPWR Circuit Voltage Turn ignition off. Install EEC power relay. Turn ignition on. With PCM connected, measure voltage between test pins No. 37 and 57 (VPWR) and test pins No. 40 and 60 (PWR GND) and 46 (SIG RTN) at breakout box. If voltage is 10.5 volts or more, repair circuit between PCM and EEC power relay. Repeat QUICK TEST. If voltage is less than 10.5 volts, replace EEC power relay. Repeat QUICK TEST. CIRCUIT TEST C - REFERENCE VOLTAGE Diagnostic Aids Perform this test when a check for VREF signal has failed in sensor input CIRCUIT TEST DA and CIRCUIT TEST DS, or if directed by CIRCUIT TEST AA, CIRCUIT TEST AC, or CIRCUIT TEST QA. SIG RTN is a dedicated ground used by most EEC-IV system sensors. VREF is a 5-volt reference voltage that is continuously output by PCM. This consistent voltage signal is used on all 3-wire sensors. This circuit test is only intended to diagnose SIG RTN, VREF, TP, EVP, DPFE, MAP and BARO circuits.

32 Article Text (p. 32) TEST PIN NO. 26 (VREF) WIRE COLOR IDENTIFICATION TABLE Application Wire Color All Models... Brown/White TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION TABLE Application Wire Color All Models... Gray/Red Fig. 14: Reference Voltage Circuits & Connector Terminal ID (4.0L) 1) Check Battery Power Circuit Turn ignition off, and wait 10 seconds. Disconnect PCM 60-pin connector. Inspect for damage and repair as necessary. Install Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure and record voltage between breakout box test pin No. 37 and SIG RTN terminal of Data Link Connector (DLC). Measure and record voltage across battery terminals. If both readings are less than 10.5 volts, or if they differ by more than one volt, reconnect sensor (if applicable) and go to CIRCUIT TEST B. If voltage readings are 10.5 volts or more and do not differ from one another by more than one volt, go to next step. 2) Check VREF Voltage With breakout box installed and PCM connected, turn ignition on. Measure voltage between test pins No. 26 and 46 at breakout box. If voltage is 4-6 volts, go to next step. If voltage is more than 6 volts, go to step 4). If voltage is less than 4 volts, go to step 5). 3) Check VREF & SIG RTN Circuit Continuity Turn ignition off. If directed here by a sensor test, ensure sensor is disconnected. Disconnect PCM from breakout box. Measure resistance between test pin No. 26 and VREF terminal at wiring harness

33 Article Text (p. 33) connector of applicable sensor. Measure resistance between test pin No. 46 and SIG RTN circuit terminal at wiring harness connector of applicable sensor. If both readings are less than 5 ohms, VREF circuit is okay. If either reading is 5 ohms or more, repair open VREF or SIG RTN circuit and repeat QUICK TEST. 4) Check For Excess VREF Circuit Voltage Turn ignition off. With breakout box installed, disconnect PCM and scan tester or Star tester (if applicable). Turn ignition on. Measure voltage between test pin No. 26 and battery ground. If voltage is less than 0.5 volt, replace PCM and repeat QUICK TEST. If voltage is 0.5 volt or more, repair short to battery power in wiring harness. Remove breakout box and repeat QUICK TEST. Replace PCM if fault still occurs. 5) Check For Shorted Throttle Position (TP) Sensor Turn ignition off. Connect PCM to breakout box. Disconnect TP sensor from wiring harness. Turn ignition on. Measure voltage between test pins No. 26 and 46 at breakout box. If voltage is 4 volts or more, replace TP sensor and repeat QUICK TEST. On models with EVP or DPFE sensor, if voltage is less than 4 volts, go to next step. On all other models, if voltage is less than 4 volts, go to step 8). 6) Check For Shorted EVP/DPFE Sensor Turn ignition off. Disconnect EVP/DPFE sensor. Turn ignition on. Measure voltage between test pins No. 26 and 46. If voltage is 4 volts or more, replace EVP/DPFE sensor and repeat QUICK TEST. If voltage is less than 4 volts, reconnect EVP/DPFE sensor and go to next step. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 8). No test procedures have been omitted. 8) Check For Shorted MAP/BARO Sensor On models not equipped with a MAP/BARO sensor, go to next step. On all other models, turn ignition off. Disconnect MAP/BARO sensor. Turn ignition on. Measure voltage between test pins No. 26 and 46. If voltage is 4 volts or more, replace MAP/BARO sensor. Remove breakout box, and repeat QUICK TEST. If voltage is less than 4 volts, reconnect MAP/BARO sensor and go to next step. 9) Check VREF Circuit For Short To Ground Turn ignition off. Disconnect PCM, TP sensor, MAP/BARO sensor and EVP/DPFE sensor (if equipped). Measure resistance between test pin No. 26 and test pins No. 20, 40, 46 and 60. If any reading is less than 1000 ohms, repair short to ground. Remove breakout box, and repeat QUICK TEST. If original problem still exists, replace PCM and repeat QUICK TEST. If readings are 1000 ohms or more, replace PCM and repeat QUICK TEST. CIRCUIT TEST DA - TEMPERATURE SENSOR TEST (ECT & IAT) Diagnostic Aids Perform this test only when directed by QUICK TEST. Ambient air temperature must be at least 50ÍF (10ÍC) to receive valid input from IAT sensor. Engine coolant temperature must be greater than 50ÍF