DIAGNOSIS AND TESTING

308-07A-1 DIAGNOSIS AND TESTING Electronic Shift Visual Inspection Chart Mechanical Electrical 308-07A-1 Refer to Wiring Diagrams Cell 34 for schematic and Halfshafts Junction box (JB) mini connector information. Integrated wheel ends fuses: (IWE) 11 (10A) (IWE Special Tool(s) Shift motor vacuum solenoid) Driveshaft and universal 20 (15A) Worldwide Diagnostic System joints 29 (15A) (WDS) Vacuum leaks Junction box (JB) fuse Vehicle Communication Module Fluid leaks 111 (30A) (VCM) with appropriate Matching tire sizes Wiring harness adapters, or equivalent Transfer case Mode select switch diagnostic tool 73III Automotive Meter 105-R0057 or equivalent (MSS) Synchronization clutch Connector(s) IWE vacuum solenoid Circuitry 3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step. 4. If the cause is not visually evident, connect the 88 Digital Multimeter or diagnostic tool to the data link connector and equivalent select the vehicle to be tested from the 105-R0053 diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle: Flex Probe Kit 105-R025B Inspection and Verification Electronic Shift check that the program card is correctly installed (if using NGS+). check the connections to the vehicle. check the ignition switch position. 5. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual. 6. Carry out the data link diagnostics test. If the diagnostic tool responds with: SCP+, SCP-, UBP or CAN or ISO circuits 1. Verify the customer concern. fault; all electronic control units no response/not equipped, refer to Section 2. Visually inspect for obvious signs of 418-00. mechanical or electrical damage. response/not equipped for powertrain control module (PCM). Refer to Section 418-00 to diagnose module communication problems. response/not equipped for 4x4 module (PCM), GO to Pinpoint Test J. Copyright 2004, Ford Motor Company Last updated: 1/15/2009

308-07A-2 DIAGNOSIS AND TESTING 308-07A-2 System passed, retrieve and record the 7. If the DTCs retrieved are related to the concern, continuous diagnostic trouble codes (DTCs), go to the 4x4 Module (PCM) DTC Index to erase the continuous DTCs and carry out the continue diagnostics. self-test diagnostics for the 4x4 module 8. If no DTCs related to the concern are retrieved, (PCM). GO to Symptom Chart. 4x4 Module (PCM) Diagnostic Trouble Code (DTC) Index DTC Description Source Action B1317 Battery Voltage High 4x4 Module CHECK the battery and charging system (PCM) for faults. REFER to Section 414-00. CLEAR the DTC. REPEAT the self-test. B1318 Battery Voltage Low 4x4 Module CHECK the battery and charging system (PCM) for faults. REFER to Section 414-00. CLEAR the DTC. REPEAT the self-test. B1342 ECU is Defective 4x4 Module CLEAR the DTC. REPEAT the self-test. (PCM) If DTC B1342 is retrieved, INSTALL a 4x4 module (integral to PCM). For 4.6L engine, REFER to Section 303-14. REPEAT the self-test. C1728 Transfer Case Unable to Transition 4x4 Module GO to Pinpoint Test L. Between 2WD HIGH and 4WD HIGH (PCM) C1729 Transfer Case Unable to Transition 4x4 Module GO to Pinpoint Test M. Between 4WD HIGH and 4WD LOW (PCM) C1979 IWE Solenoid Circuit Failure 4x4 Module GO to Pinpoint Test K. (PCM) C1980 IWE Solenoid Circuit Short to Battery 4x4 Module GO to Pinpoint Test K. (PCM) P1812 Transmission 4-Wheel Drive Mode Select 4x4 Module GO to Pinpoint Test L. Circuit Failure (PCM) P1815 Transmission 4-Wheel Drive Mode Select 4x4 Module GO to Pinpoint Test L. Short Circuit to Ground (PCM) P1820 Transfer Case Clockwise Shift Relay 4x4 Module GO to Pinpoint Test L. Coil Circuit Failure (PCM) P1822 Transfer Case Clockwise Shift Relay 4x4 Module GO to Pinpoint Test L. Coil Short Circuit To Battery (PCM) P1824 Transmission 4-Wheel Drive Clutch 4x4 Module GO to Pinpoint Test N. Relay Circuit Failure (PCM) P1826 Transmission 4-Wheel Drive Low Clutch 4x4 Module GO to Pinpoint Test N. Relay Short Circuit to Battery (PCM) P1827 Transmission 4-Wheel Drive Low Clutch 4x4 Module GO to Pinpoint Test N. Relay Short Circuit to Ground (PCM) P1828 Transfer Case Counterclockwise Shift 4x4 Module GO to Pinpoint Test L. Relay Coil Circuit Failure (PCM) P1830 Transfer Case Counterclockwise Shift 4x4 Module GO to Pinpoint Test L. Relay Coil Short Circuit To Battery (PCM) P1849 Transmission Transfer Case Contact Plate 4x4 Module GO to Pinpoint Test L. A Short Circuit to Ground (PCM) P1853 Transmission Transfer Case Contact Plate 4x4 Module GO to Pinpoint Test L. B Short Circuit to Ground (PCM)

308-07A-3 DIAGNOSIS AND TESTING DTC Description Source Action P1857 Transmission Transfer Case Contact Plate 4x4 Module GO to Pinpoint Test L. C Short Circuit to Ground (PCM) P1861 Transmission Transfer Case Contact Plate 4x4 Module GO to Pinpoint Test L. D Short Circuit to Ground (PCM) P1867 Transmission Transfer Case Contact Plate 4x4 Module GO to Pinpoint Test L. General Circuit Failure (PCM) P1891 Transmission Transfer Case Contact Plate 4x4 Module GO to Pinpoint Test L. Ground Return Open Circuit (PCM) 308-07A-3 U1900 CAN Communication BUS Fault 4x4 Module DIAGNOSE the module communication Received Error (PCM) network. REFER to Section 418-00. U2023 Fault Received From External de 4x4 Module DIAGNOSE the module communication (PCM) network. REFER to Section 418-00. U2051 One Or More Calibration Files 4x4 Module Method 3 programming fault. REFER to Missing/Corrupt (PCM) Section 418-00 for 4x4 module (PCM) programming information. Symptom Chart Symptom Chart Condition Possible Sources Action communication with the Diagnostic tool. GO to Pinpoint Test J. 4x4 module (PCM) Data link connector (DLC). 4x4 module (PCM). Circuitry. The instrument cluster 4L and Instrument cluster. GO to Pinpoint Test R. 4H indicators do not operate Circuitry. correctly/do not operate 4x4 module (PCM). The vehicle does not shift Mode select switch (MSS). GO to Pinpoint Test L. between 2WD and 4WD Transfer case. modes correctly Transfer case clutch. Integrated wheel ends (IWEs). 4x4 module (PCM). Circuitry. The vehicle does not shift Transfer case. GO to Pinpoint Test M. between 4H and 4L modes Mode select switch. correctly 4x4 module (PCM). Transmission drag torque. 4WD does not engage at Transfer case clutch coil. GO to Pinpoint Test N. speed correctly 4x4 module (PCM). Integrated wheel ends (IWEs). The front axle does not Mode select switch. GO to Pinpoint Test K. engage/disengage Integrated wheel ends (IWE). correctly/makes noise in 2H IWE solenoid. under heavy throttle Vacuum leaks. 4x4 module (PCM). Front halfshaft. The 4x4 system jumps out of Transfer case. GO to Pinpoint Test O. gear IWE vent. Mode select switch (MSS). Straightline driveline wind-up Tire inflation pressure. GO to Pinpoint Test P. Tire and wheel size. Tire wear. Axle ratio.

308-07A-4 DIAGNOSIS AND TESTING Symptom Chart 308-07A-4 Condition Possible Sources Action Grinding noise during 4WD Front halfshaft speeds not GO to Pinpoint Test L. engagement, especially at turning at the same speed. high speeds Sychronization clutch. Flashing 4x4 high and 4x4 Loss of CAN communication CHECK the instrument low indicators 3 times every between 4x4 module (PCM) cluster for faults. REFER to 2 minutes. and instrument cluster. Section 413-01. communication with the CHECK 4x4 module (PCM) 4x4 module (PCM). communication. GO to Pinpoint Test J. The transfer case makes noise Tire inflation pressure. MAKE SURE that all tires Tire and wheel size. and wheels are the same size and that the inflation pressures are correct. Tire tread wear. CHECK tire tread wear to see if there is more than 0.15 mm (0.06 in) difference in tread wear between front and rear. INTERCHANGE one front wheel and one rear wheel. ROAD TEST again. Internal components. OPERATE the vehicle in all transmission gears. If there is noise in the transmission in NEUTRAL, or in some gears and not in others, REMOVE and REPAIR the transmission. REFER to Section 307-01. If there is noise in all gears, DISASSEMBLE the transfer case. REFER to Section 308-07B. CHECK the planetary gears, the bearings, the upper and lower drive sprockets and drive chain for damage. INSTALL new parts as necessary. Fluid level. FILL with automatic transmission fluid. REFER to Section 308-07B. Unable to duplicate customer 4x4 system and/or related CARRY OUT the electronic concern components. shift on the fly (ESOF) Functional Test. GO to Pinpoint Test Q.

308-07A-5 DIAGNOSIS AND TESTING Connector Circuit Reference 308-07A-5 4x4 Module (PCM) C175b (body) Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 2 CKT 1827 (WH/LG) CAN Bus+ Less than 5 ohms between the DLC and the communications circuit. module in concern. Greater than 10,000 ohms between the DLC and ground with all network modules disconnected. 3 CKT 1828 (PK/LG) CAN Bus- Less than 5 ohms between the DLC and the communications circuit. module in concern. Greater than 10,000 ohms between the DLC and ground with all network modules disconnected. 12 CKT 1861 (RD) Power circuit to 4x4 module Hot at all times. 9 volts or greater between (PCM) for 4WD functionality. 4x4 module (PCM) and ground. 10,000 ohms or greater between the 4x4 module (PCM) and ground with the 4x4 module (PCM) disconnected. 13 CKT 1865 (WH/OG) Power circuit to 4x4 Hot at all times. 9 volts or greater between module (PCM) for 4WD functionality. 4x4 module (PCM) and ground. 10,000 ohms or greater between the 4x4 module (PCM) and ground with the 4x4 module (PCM) disconnected. 14 CKT 975 (BN/YE) Transfer case shift motor 10,000 ohms or greater between the 4x4 clockwise rotation (low to high) relay control module (PCM) and ground with the 4x4 circuit. module (PCM) disconnected. 5 ohms or less between the 4x4 module (PCM) and the clockwise rotation relay. 9 volts or greater between the 4x4 module (PCM) and ground with the clockwise relay connected. 15 CKT 976 (OG) Transfer case shift motor 10,000 ohms or greater between the 4x4 counterclockwise rotation (high to low) relay module (PCM) and ground with the 4x4 control circuit. module (PCM) disconnected. 5 ohms or less between the 4x4 module (PCM) and the counterclockwise rotation relay. 9 volts or greater between the 4x4 module (PCM) and ground with the clockwise relay connected. 16 CKT 605 (RD) Integrated wheel end (IWE) 10,000 ohms or greater between the 4x4 solenoid control circuit. module (PCM) and ground with the 4x4 module (PCM) and the IWE solenoid disconnected. 5 ohms or less between the 4x4 module (PCM) and IWE solenoid.

308-07A-6 DIAGNOSIS AND TESTING Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 308-07A-6 31 CKT 682 (DB) 4WD Mode select switch 10,000 ohms or greater between the 4x4 (MSS) signal return circuit. module (PCM) and ground with the 4x4 module (PCM) and MSS disconnected. 5 ohms or less between the 4x4 module (PCM) and MSS. 32 CKT 780 (DB) 4WD Mode select switch 10,000 ohms or greater between the 4x4 (MSS) signal circuit. module (PCM) and ground with the 4x4 module (PCM) and MSS disconnected. 5 ohms or less between the 4x4 module (PCM) and MSS. 51 CKT 361 (RD) VPWR circuit. Hot in RUN/START. 9 volts or greater between 4x4 module (PCM) and ground. 10,000 ohms or greater between the 4x4 module (PCM) and ground with the 4x4 module (PCM) disconnected. 52 CKT 361 (RD) VPWR circuit. Hot in RUN/START. 9 volts or greater between 4x4 module (PCM) and ground. 10,000 ohms or greater between the 4x4 module (PCM) and ground with the 4x4 module (PCM) disconnected. 53 CKT 361 (RD) VPWR circuit. Hot in RUN/START. 9 volts or greater between 4x4 module (PCM) and ground. 10,000 ohms or greater between the 4x4 module (PCM) and ground with the 4x4 module (PCM) disconnected. 67 CKT 570a (BK/WH) 4x4 module (PCM) 5 ohms or less between the 4x4 module ground circuit. (PCM) and ground. 68 CKT 570b (BK/WH) 4x4 module (PCM) 5 ohms or less between the 4x4 module ground circuit. (PCM) and ground. 69 CKT 570c (BK/WH) 4x4 module (PCM) 5 ohms or less between the 4x4 module ground circuit. (PCM) and ground. 70 CKT 570d (BK/WH) 4x4 module (PCM) 5 ohms or less between the 4x4 module ground circuit. (PCM) and ground.

308-07A-7 DIAGNOSIS AND TESTING 4x4 Module (PCM) C175t (transmission) 308-07A-7 Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 6 CKT 770 (WH) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 1. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 7 CKT 771 (VT/YE) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 2. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 8 CKT 772 (LB) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 3. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 9 CKT 778 (OG) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 4. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 46 CKT 782 (BN/WH) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal return. module (PCM) and ground with the 4x4 module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 48 CKT 92 (LB/YE) Transfer case 10,000 ohms or greater between the 4x4 synchronization clutch signal return circuit. module (PCM) and ground with the 4x4 module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 49 CKT 779 (BN) Transfer case synchronization 10,000 ohms or greater between the 4x4 clutch power supply circuit. module (PCM) and ground with the 4x4 module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case.

308-07A-8 DIAGNOSIS AND TESTING Mode Select Switch (MSS) C284 308-07A-8 Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 2 CKT 682 (DB) 4WD Mode select switch 10,000 ohms or greater between the 4x4 (MSS) signal return circuit. module (PCM) and ground with the 4x4 module (PCM) and MSS disconnected. 5 ohms or less between the 4x4 module (PCM) and MSS. 3 CKT 780 (DB) 4WD Mode select switch 10,000 ohms or greater between the 4x4 (MSS) signal circuit. module (PCM) and ground with the 4x4 module (PCM) and MSS disconnected. 5 ohms or less between the 4x4 module (PCM) and MSS. Transfer Case C350 Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 1 CKT 771 (VT/YE) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 2. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 5 CKT 770 (WH) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 1. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 9 CKT 772 (LB) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 3. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case.

308-07A-9 DIAGNOSIS AND TESTING Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 308-07A-9 10 CKT 782 (BN/WH) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal return. module (PCM) and ground with the 4x4 module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 12 CKT 92 (LB/YE) Transfer case 10,000 ohms or greater between the 4x4 synchronization clutch signal return circuit. module (PCM) and ground with the 4x4 module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 13 CKT 778 (OG) Transfer case shift motor 10,000 ohms or greater between the 4x4 position contact plate encoder signal position module (PCM) and ground with the 4x4 4. module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. 14 CKT 785 (BK/LG) Transfer case shift motor 10,000 ohms or greater between the counterclockwise rotation power supply counterclockwise rotation relay and ground circuit. with the counterclockwise relay and transfer case disconnected. 5 ohms or less between the counterclockwise relay and the transfer case. 15 CKT 786 (RD) Transfer case shift motor 10,000 ohms or greater between the clockwise rotation power supply circuit. clockwise rotation relay and ground with the clockwise relay and transfer case disconnected. 5 ohms or less between the clockwise relay and the transfer case. 16 CKT 779 (BN) Transfer case synchronization 10,000 ohms or greater between the 4x4 clutch power supply circuit. module (PCM) and ground with the 4x4 module (PCM) and the transfer case disconnected. 5 ohms or less between the 4x4 module (PCM) and the transfer case. Integrated Wheel End (IWE) Solenoid C1290 Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 1 CKT 605 (RD) IWE solenoid control circuit. 10,000 ohms or greater between the IWE solenoid and ground with the IWE solenoid and the 4x4 module (PCM) disconnected. 5 ohms or less between the IWE solenoid and the 4x4 module (PCM). 2 CKT 883 (PK/LB) IWE solenoid power Hot at all times. 9 volts or greater between supply circuit. the IWE solenoid and ground. 10,000 ohms or greater between the IWE solenoid and ground with the IWE solenoid disconnected.

308-07A-10 DIAGNOSIS AND TESTING Shift Motor Clockwise Rotation Relay/Shift Motor Counterclockwise Rotation Relay 308-07A-10 Pin Number(s) Circuit Designation/Description rmal Condition/Measurement 1 (CW) CKT 975 (BN/YE) Transfer case shift motor 10,000 ohms or greater between the clockwise rotation relay control circuit. clockwise relay and ground with the clockwise relay and the 4x4 module (PCM) disconnected. 5 ohms or less between the clockwise relay and the 4x4 module (PCM). 1 (CCW) CKT 976 (OG) Transfer case shift motor 10,000 ohms or greater between the counterclockwise rotation relay control clockwise relay and ground with the circuit. clockwise relay and the 4x4 module (PCM) disconnected. 5 ohms or less between the clockwise relay and the 4x4 module (PCM). 2 (CW) CKT 704d (DG/LG) Transfer case shift Hot at all times. 9 volts or greater between motor clockwise rotation relay power supply the clockwise relay and ground. circuit. 2 (CCW) CKT 704b (DG/LG) Transfer case shift Hot at all times. 9 volts or greater between motor counterclockwise rotation relay power the clockwise relay and ground. supply circuit. 3 (CW) CKT 786 (RD) Transfer case shift motor 10,000 ohms or greater between the clockwise rotation power supply circuit. clockwise rotation relay and ground with the clockwise relay and transfer case disconnected. 5 ohms or less between the clockwise relay and the transfer case. 3 (CCW) CKT 785 (BK/LG) Transfer case shift motor 10,000 ohms or greater between the counterclockwise rotation power supply clockwise rotation relay and ground with the circuit. clockwise relay and transfer case disconnected. 5 ohms or less between the clockwise relay and the transfer case. 4 CKT 57a/b (BK) Relay ground circuit. 5 ohms or less between connector pin and ground. Pinpoint Tests Pinpoint Test J: Communication With the 4x4 Module (PCM) Refer to Wiring Diagrams Cell 34 for schematic and connector information. rmal Operation In order for the 4x4 module (PCM) to communicate with the scan tool, the operating voltage required to supply the 4x4 module (PCM) is in a range between 9 and 16 volts. Voltage is supplied by circuit 1861 (RD) and circuit 1865 (WH/OG). Possible Causes Power supply: circuit 1861 (RD) circuit 1865 (WH/OG) Power distribution junction box (PDJB) mini-fuses: 20 (15A) 29 (15A) Charging system. Battery.

308-07A-11 DIAGNOSIS AND TESTING J1 J2 J3 J4 J5 J6 J7 PINPOINT TEST J: NO COMMUNICATION WITH THE 4x4 MODULE (PCM) NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes. 308-07A-11 CHECK FOR DIAGNOSTIC TOOL COMMUNICATION WITH THE VEHICLE Verify diagnostic tool communication with the vehicle. If using the using WDS, follow the directions and carry out the network test. If using NGS, verify that the correct cable is used and the GO to J2. vehicle and engine selection information is correct. WDS: Does the network test pass for the PCM? REFER to the appropriate diagnostic tool NGS: Does the diagnostic tool communicate with the PCM? manual for further diagnosis. CHECK FOR VOLTAGE INPUT TO THE 4x4 MODULE (PCM) Disconnect: 4x4 Module (PCM) C175b. Measure the voltage between C175b-12, circuit 1861 (RD), harness side and ground; and between C175b-13, circuit 1865 GO to J6. (WH/OG) and ground. Are the voltages greater than 9 volts? GO to J3. CHECK THE POWER DISTRIBUTION JUNCTION BOX (PDJB) MINI-FUSES Check PDJB mini-fuses 20 (15A) and 29 (15A). Are the fuses okay? GO to J4. CHECK circuit 1861 (RD) and circuit 1865 (WH/OG). REPAIR as necessary. REPEAT the self-test. CHECK FOR BATTERY VOLTAGE FROM THE JUNCTION BOX (JB) Ignition ON. Measure the voltage between JB input side fuse cavity 20 and REPAIR or INSTALL new components as ground; and between JB input side fuse cavity 29 and ground. necessary. REPEAT the self-test. Are the voltages greater than 9 volts? GO to J5. CHECK THE BATTERY VOLTAGE WITH THE ENGINE RUNNING Start the engine. Measure the battery voltage at the positive battery terminal. REPAIR circuit 1861 (RD) or 1865 Is the voltage greater than 9 volts? (WH/OG). REPEAT the self-test. CHECK the charging system. REFER to Section 414-00. CHECK THE GROUND CIRCUITS FOR AN OPEN Disconnect the battery ground cable. Refer to Section 414-01. Disconnect: 4x4 Module (PCM) C175b. Measure the resistance between C175b-66, circuit 567 (LB/YE) and ground; and between C175b-67, circuits 570a C175b-68, GO to J7. circuit 570b C175b-69, circuits 570c C175b-70 circuit 570d, (BK/WH) and ground. REPAIR the affected circuit(s). REPEAT Are the resistances less than 5 ohms? the self-test. CHECK THE VOLTAGE ON GROUND CIRCUITS Measure the voltage between C175b-66, circuit 567 (LB/YE) and ground; and between C175b-67, circuit 570a, C175b-68, circuit REPAIR the affected circuit(s). REPEAT 570b, C175b-69, circuit 570c, C175b-70, circuit 570d and the self-test. ground. Is voltage present? Disconnect all 4x4 module (PCM) connectors. CHECK for corrosion, and/or pushed-out pins. The condition may have been caused by a loose or corroded connector. REPAIR or CLEAN as necessary. If not, INSTALL a new 4x4 module (integral to the PCM). REFER to Section 303-14. TEST the system for normal operation.

308-07A-12 DIAGNOSIS AND TESTING Pinpoint Test K: The Front Axle Does t Engage/Disengage Correctly/Makes ise In 2H Under Heavy Throttle rmal Operation In 2WD, the 4x4 module (PCM) supplies a ground path to the IWE solenoid to apply vacuum to the integrated wheel ends (disengaging the front hubs from the front axle). In 4WD, the 4x4 module (PCM) does not supply the ground path to the IWE solenoid, vacuum is not applied to the integrated wheel ends and an internal spring keeps the hubs engaged. Systematically check the necessary inputs and outputs at the 4x4 module (PCM), internal components of the transfer case, mode select switch, IWE components and drive axles. Possible Causes Mode select switch Integrated wheel end (IWE) IWE solenoid Transfer case Vacuum leaks Front axle assembly 4x4 module (PCM) Circuit 605 (RD) Circuit 883 (BK/LB) CJB fuse 11 (10A) 308-07A-12 PINPOINT TEST K: THE FRONT AXLE DOES NOT ENGAGE/DISENGAGE CORRECTLY/MAKES NOISE IN 2H UNDER HEAVY THROTTLE K1 K2 K3 CHECK FOR DTCs Ignition OFF. Connect the scan tool. If DTC C1979 is retrieved, GO to K13. Ignition ON. If DTC C1980 is retrieved, GO to K15. Carry out the on-demand self test. Are DTCs C1979 or C1980 present? GO to K2. CHECK FOR GRINDING NOISES AT HIGH SPEEDS Turn the MSS from 2WD to 4WD at rest. Drive the vehicle. Turn the MSS from 2WD to 4WD while driving the vehicle at low speed. Turn the MSS case from 2WD to 4WD while driving the vehicle REFER to Section 205-00 to diagnose at high speed. excessive front axle noise/chatter/grinding Is the axle system fully functional at rest, but there is a during 4X4 engagement. grinding noise during engagement, especially at high speed? GO to K3. CHECK THE TRANSFER CASE SHIFT TO 2H Ignition OFF. Connect the scan tool. Ignition ON. NOTE: If it is difficult to read the motor position, use the active command to energize the transfer case motor contact plate position return circuit. Monitor the 4x4 module (PCM) PID for the contact plate position while switching the MSS to 2H. Mode Select Switch Position K4 Contact Plate Position 1 (A) 2 (B) 3 (C) 4 (D) 2H CLOSED OPEN CLOSED CLOSED 4H OPEN CLOSED CLOSED OPEN 4L OPEN CLOSED OPEN CLOSED GO to K4. Does the 4x4 module (PCM) PID and instrument cluster indicator lamp indicate that vehicle shifted into 2H? GO to Pinpoint Test L. CHECK THE IWE DISENGAGEMENT Raise and support the vehicle off the ground until the front wheels can be spun freely. Refer to Section 100-02.

308-07A-13 DIAGNOSIS AND TESTING 308-07A-13 PINPOINT TEST K: THE FRONT AXLE DOES NOT ENGAGE/DISENGAGE CORRECTLY/MAKES NOISE IN 2H UNDER HEAVY THROTTLE K4 K5 CHECK THE IWE DISENGAGEMENT NOTE: The engine must be idling during the following steps to supply vacuum to the IWE solenoid. Start the engine and allow to idle. Switch the MSS to 2H. Rotate the left front tire one revolution forward and one revolution backward while observing the left front halfshaft. Rotate the right front tire one revolution forward and one GO to K10. revolution backward while observing the right front halfshaft. Did either front halfshaft rotate? GO to K5. CHECK THE TRANSFER CASE SHIFT INTO 4H NOTE: If it is difficult to read the motor position, use the active command to energize the transfer case motor contact plate position return circuit. Monitor the 4x4 module (PCM) PID for the contact plate position while switching the MSS to 4H. Mode Select Switch Position K6 K7 K8 Contact Plate Position 1 (A) 2 (B) 3 (C) 4 (D) 2H CLOSED OPEN CLOSED CLOSED 4H OPEN CLOSED CLOSED OPEN 4L OPEN CLOSED OPEN CLOSED GO to K6. Does the 4x4 module (PCM) PID and instrument cluster indicator lamp indicate that the MSS in 4H? GO to Pinpoint Test L. CHECK THE IWE ENGAGEMENT Raise and support the vehicle off the ground until the front wheels can be spun freely. Refer to Section 100-02. NOTE: The engine must be idling during the following steps to supply vacuum to the IWE solenoid. Start the engine and allow to idle. Switch the MSS to 4H. CHECK that all driveline fasteners are Rotate the left front tire one revolution forward and one present and tightened to specification. revolution backward while observing the left front halfshaft. REFER to Section 205-00 for further Rotate the right front tire one revolution forward and one diagnosis of the front axle. revolution backward while observing the right front halfshaft. Did both front halfshafts rotate? GO to K7. CHECK THE IWE SOLENOID OUTPUT IN 4H NOTE: The engine must be idling during the following steps to supply vacuum to the IWE solenoid. Start the engine. Disconnect the output vacuum line at the IWE solenoid. Switch the MSS to 4H. Key in OFF position. GO to K25. Measure the vacuum at the output port of the IWE solenoid. Is the vacuum less than 25 mm (1 in) Hg? GO to K8. CHECK THE IWE SOLENOID OUTPUT IN 4H WITH THE DIAGNOSTIC TOOL Ignition OFF. Connect the scan tool. NOTE: The engine must be idling during the following steps to supply vacuum to the IWE solenoid. Start the engine. Enter the following diagnostic mode on the diagnostic tool: Active Command. Using the diagnostic tool, command the IWE solenoid to engage the IWEs (solenoid OFF). End active command. GO to K19. Measure the vacuum at the output port of the IWE solenoid. Is the vacuum less than 25 mm (1 in) Hg? GO to K9.

308-07A-14 DIAGNOSIS AND TESTING 308-07A-14 PINPOINT TEST K: THE FRONT AXLE DOES NOT ENGAGE/DISENGAGE CORRECTLY/MAKES NOISE IN 2H UNDER HEAVY THROTTLE K9 K10 K11 K12 K13 CHECK THE IWE SOLENOID Disconnect: IWE Solenoid C1290. Measure the vacuum at the output port of the IWE solenoid. End active command. GO to K17. Is the vacuum less than 25 mm (1 in) Hg? End active command. INSTALL a new IWE solenoid. REPEAT the self-test. CHECK THE IWE SOLENOID OUTPUT VACUUM IN 2WD NOTE: The engine must be idling during the following steps to supply vacuum to the IWE solenoid. Start the engine. Disconnect the output vacuum line at the IWE solenoid. Switch the MSS to 2H. GO to K20. Measure the vacuum at the output port of the IWE solenoid. Is the vacuum greater than 254 mm (10 in) Hg? GO to K11. CHECK THE IWE SOLENOID INPUT VACUUM Measure the vacuum at the input port of the IWE solenoid. Is the vacuum greater than 254 mm (10 in) Hg? GO to K12. REPAIR the vacuum leak. CLEAR the DTCs. REPEAT the self-test. CHECK THE IWE SOLENOID OUTPUT IN 2WD WITH THE DIAGNOSTIC TOOL Ignition OFF. Connect the scan tool. NOTE: The engine must be idling during the following steps to supply vacuum to the IWE solenoid. Start the engine. Enter the following diagnostic mode on the diagnostic tool: Active Command. Using the diagnostic tool, command the IWE solenoid to disengage the IWEs (IWE solenoid ON). End active command. GO to K19. Measure the vacuum at the output port of the IWE solenoid. Is the vacuum greater than 254 mm (10 in) Hg? End active command. GO to K13. CHECK CIRCUIT 883 (BK/LB) FOR VOLTAGE Ignition OFF. Disconnect: IWE Solenoid C1290. Measure the voltage between IWE solenoid C1290-2, circuit 883 (BK/LB) and ground. K14 GO to K14. CHECK CJB fuse 11 (10A). VERIFY that the fuse blows when the air conditioning (A/C) system compressor cycles. If this occurs, REFER to Section 412-00. REPAIR the circuit as necessary. CLEAR Is the voltage greater than 9 volts? the DTCs. REPEAT the self-test. CHECK THE IWE SOLENOID OPERATION Connect: IWE Solenoid C1290.

308-07A-15 DIAGNOSIS AND TESTING 308-07A-15 PINPOINT TEST K: THE FRONT AXLE DOES NOT ENGAGE/DISENGAGE CORRECTLY/MAKES NOISE IN 2H UNDER HEAVY THROTTLE K14 K15 CHECK THE IWE SOLENOID OPERATION NOTE: The engine must be idling during the following steps to supply the vacuum required for the IWEs to engage and disengage. Start the engine. Connect a 10 amp fused jumper wire between the IWE solenoid DISCONNECT the fused jumper. GO to C1290-1, circuit 605 (RD), component side and ground. K15. Measure the vacuum at the IWE solenoid output vacuum port. Is the IWE solenoid output port vacuum greater than 254 INSTALL a new IWE solenoid. CLEAR the mm (10 in) Hg? DTCs. REPEAT the self-test. CHECK CIRCUIT 605 (RD) FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: IWE Solenoid C1290. Disconnect: 4x4 Module (PCM) C175b. Ignition ON. Measure the voltage between IWE solenoid C1290-1, circuit 605 (RD), harness side and ground. K16 REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. Is voltage present? GO to K16. CHECK CIRCUIT 605 (RD) FOR AN OPEN Ignition OFF. Measure the resistance between IWE solenoid C1290-1, circuit 605 (RD), harness side and 4x4 module (PCM) C175b-16, circuit 605 (RD), harness side. K17 GO to K17. REPAIR the circuit. CLEAR the DTCs. Is the resistance less than 5 ohms? REPEAT the self-test. CHECK CIRCUIT 605 (RD) FOR A SHORT TO GROUND Ignition OFF. Disconnect: 4x4 Module (PCM) C175b.

308-07A-16 DIAGNOSIS AND TESTING 308-07A-16 PINPOINT TEST K: THE FRONT AXLE DOES NOT ENGAGE/DISENGAGE CORRECTLY/MAKES NOISE IN 2H UNDER HEAVY THROTTLE K17 CHECK CIRCUIT 605 (RD) FOR A SHORT TO GROUND Measure the resistance between IWE solenoid C1290-1, circuit 605 (RD), harness side and ground. K18 GO to K18. REPAIR the circuit. CLEAR the DTCs. Is the resistance greater than 10,000 ohms? REPEAT the self-test. CHECK THE IWE SOLENOID RESISTANCE Measure the resistance between IWE solenoid C1290-1 and C1290-2, component side. K19 K20 GO to K19. INSTALL a new IWE solenoid. CLEAR the Is the resistance between 68 and 78 ohms? DTC(s). REPEAT the self-test. CHECK THE 4x4 MODULE Disconnect all 4x4 module (PCM) connectors. Check for: INSTALL a new 4x4 module (integral to corrosion PCM). For 4.6L engine, REFER to Section pushed-out pins 303-04A. For 5.4L engine, REFER to Connect all 4x4 module (PCM) connectors and make sure they Section 303-04B. CLEAR the DTCs. are seated correctly. REPEAT the self-test. Operate the system and verify the concern is still present. Is the concern still present? The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CHECK THE IWE VACUUM SYSTEM Ignition OFF. Disconnect both vacuum lines from the IWE solenoid. Using a vacuum pump, apply 508 mm (20 in) Hg of vacuum to the IWE system through the apply vacuum circuit. GO to K21. Observe the vacuum reading. Did the vacuum drop more than 25 mm (1 in) Hg per CONNECT the vacuum lines to the IWE minute? solenoid. GO to K24.

308-07A-17 DIAGNOSIS AND TESTING 308-07A-17 PINPOINT TEST K: THE FRONT AXLE DOES NOT ENGAGE/DISENGAGE CORRECTLY/MAKES NOISE IN 2H UNDER HEAVY THROTTLE K21 K22 K23 K24 K25 K26 K27 CHECK THE RH IWE LEAK RATE Raise and support the vehicle on a hoist. Refer to Section 100-02. Disconnect the vacuum line from the larger port on the RH IWE. Apply 508 mm (20 in) Hg of vacuum to the RH IWE port and INSTALL a new IWE. REFER to Section observe vacuum reading. 205-04. GO to K19. Did the vacuum drop more than 25 mm (1 in) Hg per minute? GO to K22. CHECK THE LH IWE LEAK RATE Disconnect the vacuum line from the larger port at the LH IWE. Apply 508 mm (20 in) Hg of vacuum to the LH IWE port and INSTALL a new IWE. REFER to Section observe vacuum reading. 205-04. GO to K20. Did the vacuum drop more than 25 mm (1 in) Hg per minute? GO to K23. CHECK THE IWE VACUUM SUPPLY TUBE Disconnect both vacuum lines from the IWE solenoid. Plug both LH and RH IWE vacuum lines. Apply 508 mm (20 in) Hg of vacuum to the IWE apply vacuum circuit and observe the INSTALL new vacuum lines as necessary. vacuum reading. GO to K19. Did the vacuum drop more than 25 mm (1 in) Hg per minute? GO to K24. CHECK THE IWE VACUUM SUPPLY AT EACH IWE IN 2H Connect a hand-held vacuum gauge to the LH IWE vacuum supply tube. NOTE: The engine must be idling during the following steps to supply the vacuum required for the IWEs to engage and disengage. Start the engine. GO to K27. Switch the MSS to 2H while observing the vacuum gauge. Repeat these steps for the RH IWE. INSTALL new vacuum lines as necessary. Are the vacuum readings greater than 254 mm (10 in) Hg? GO to K20. CHECK THE LH IWE VACUUM LINE FOR AN OBSTRUCTION Disconnect both vacuum lines from the IWE solenoid. Raise and support the vehicle on a hoist. Refer to Section 100-02. Disconnect the vacuum line at the LH IWE. INSTALL a new vacuum line. CLEAR the Connect a hand vacuum pump to the LH IWE vacuum line and DTCs. REPEAT the self-test. attempt to draw a vacuum on the line. Did the vacuum pump draw a vacuum on the LH IWE CONNECT the vacuum line to the LH vacuum line? IWE. GO to K26. CHECK THE RH IWE VACUUM LINE FOR AN OBSTRUCTION Disconnect the larger vacuum line at the RH IWE. Connect a vacuum pump to the RH IWE vacuum line and INSTALL a new vacuum line. CLEAR the attempt to draw a vacuum on the line. DTCs. REPEAT the self-test. Did the vacuum pump draw a vacuum on the RH IWE vacuum line? CONNECT the vacuum line to the RH IWE. GO to K27. CHECK THE LH IWE OPERATION Raise and support the vehicle on a hoist. Refer to section Section 100-02. Connect a vacuum pump to the larger IWE vacuum port. Observe the LH halfshaft while rotating the LH front tire. Apply GO to K28. and release vacuum to manually engage and disengage the LH IWE. INSTALL a new LH IWE. REFER to Did the LH IWE disengage between 152 and 203 mm (6 to 8 Section 205-04. CLEAR the DTCs. in) Hg? REPEAT the self-test.

308-07A-18 DIAGNOSIS AND TESTING 308-07A-18 PINPOINT TEST K: THE FRONT AXLE DOES NOT ENGAGE/DISENGAGE CORRECTLY/MAKES NOISE IN 2H UNDER HEAVY THROTTLE K28 CHECK THE RH IWE OPERATION Connect a vacuum pump to the larger RH IWE vacuum port. Observe the RH halfshaft while rotating the RH front tire. Apply CLEAR the DTC(s). REPEAT the self-test. and release vacuum to manually engage and disengage the LH GO to Pinpoint Test Q. IWE. Did the RH IWE disengage between 152 and 203 mm (6 to 8 INSTALL a new RH IWE. REFER to in) Hg? Section 205-04. CLEAR the DTCs. REPEAT the self-test. Pinpoint Test L: The Vehicle Does t Shift Between 2WD And 4WD Modes Correctly rmal Operation The mode select switch communicates the operator s choice to the 4x4 module (PCM). The 4x4 module (PCM) then controls the transfer case clutch, transfer case motor and integrated wheel ends (IWEs) as necessary. If the vehicle is not responding to the operator s intentions, systematically check the necessary inputs and outputs of the 4x4 module (PCM), components of the transfer case, IWE components and halfshafts. Check all circuits for opens and shorts to power or ground. Possible Causes Transfer case Integrated wheel ends (IWE) IWE solenoid 4x4 module (PCM) Front axle assembly Circuit 605 (RD) Circuit 883 (BK/LB) Mode select switch (MSS) PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L1 L2 L3 L4 CHECK FOR DTCs Connect the scan tool. Carry out the 4x4 module (PCM) on-demand self test. If DTC P1812, GO to L5. If DTC P1815, Are DTCs retrieved? GO to L7. DTC P1867 or P1891, GO to L15. If DTC P1849, P1853, P1857, or P1861, GO to L17. If DTC P1820 or P1828, GO to L21. If DTC P1822 or P1830, GO to L28. GO to L2. CHECK THE IGNITION SWITCH STATUS PID Ignition ON. Monitor the ignition switch status PID. GO to L3. Do the ignition switch PIDs match the ignition switch positions? CHECK the ignition switch. REFER to Section 413-00. After the fault is repaired, CLEAR the DTC. REPEAT the self-test. CHECK THE MODE SELECT SWITCH (MSS) POSITION PIDS Ignition OFF. Connect the scan tool. Ignition ON. GO to L8. Monitor each MSS PID while cycling through each MSS position. Does each MSS PID agree with each switch position? GO to L4. CHECK THE MSS Ignition OFF. Disconnect: MSS C284. Measure the resistance between MSS C284, terminals 2 and 3, while rotating the switch through all positions. Refer to the following chart.

308-07A-19 DIAGNOSIS AND TESTING 308-07A-19 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L4 CHECK THE MSS Mode Select Switch (MSS) Position 4L 4H 2H Resistance 130 ohms 270 ohms 620 ohms L5 GO to L5. INSTALL a new MSS. REFER to Mode Select Switch (MSS). CLEAR the DTC(s). Are the resistance values within specification? REPEAT the self-test. CHECK CIRCUITS 682 (DB) AND 780 (DB) FOR AN OPEN Measure the resistance between MSS C284-2, harness side and 4x4 module (PCM) C175b-31, harness side, circuit 682 (DB). GO to L6. Measure the resistance between MSS C284-3, harness side and 4x4 module (PCM) C175b-32, harness side, circuit 780 (DB). REPAIR the affected circuit(s). CLEAR the Is the resistance less than 5 ohms? DTC(s). REPEAT the self-test.

308-07A-20 DIAGNOSIS AND TESTING 308-07A-20 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L6 CHECK CIRCUITS 682 (DB) AND 780 (DB) FOR SHORT TO VOLTAGE Measure the voltage between MSS C284-2, harness side and ground. L7 REPAIR the affected circuit(s). CLEAR the Measure the voltage between MSS C284-3, harness side and DTC(s). REPEAT the self-test. ground. Is voltage present? GO to L7. CHECK CIRCUITS 682 (DB) AND 780 (DB) FOR SHORT TO GROUND Measure the resistance between MSS C284-2, harness side and ground. L8 L9 GO to L29. Measure the resistance between MSS C284-3, harness side and ground. REPAIR the affected circuit(s). CLEAR the Is the resistance greater than 10,000 ohms? DTC(s). REPEAT the self-test. CHECK FOR 4H WIND-UP Switch the MSS to 4H. Drive the vehicle on a dry, hard surface in turns. GO to L11. Is wind-up present in turns? GO to L9. CHECK FOR TRANSFER CASE ENGAGEMENT Raise and support the vehicle. Refer to Section 100-02. Rotate the rear driveshaft. GO to L10. Observe the front driveshaft. Did the front driveshaft rotate? GO to L13.

308-07A-21 DIAGNOSIS AND TESTING 308-07A-21 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L10 L11 L12 L13 CHECK FOR IWE ENGAGEMENT NOTE: The engine must be at idle during the following steps to supply vacuum for IWE engagement/disengagement. Start the engine and allow to idle. Rotate the left front tire one revolution forward and one revolution backward while observing the left front halfshaft and CHECK that all driveline fasteners are universal joint. present and tightened to specification. Rotate the right front tire one revolution forward and one REFER to Section 205-00 for further revolution backward while observing the right front halfshaft and diagnosis of the front axle. universal joint. Did the front halfshafts rotate? GO to Pinpoint Test K. CHECK FOR IWE DISENGAGEMENT Switch the MSS to 2H. Rotate the left front tire one revolution forward and one revolution backward while observing the left front halfshaft and universal joint. Rotate the right front tire one revolution forward and one revolution backward while observing the right front halfshaft and GO to Pinpoint Test K. universal joint. Did either front axle shaft and universal joint rotate? GO to L12. CHECK FOR TRANSFER CASE DISENGAGEMENT Raise the vehicle on hoist. Refer to Section 100-02. Rotate the rear driveshaft while observing the front driveshaft. The system is functioning correctly. Does the front driveshaft rotate? GO to L13. CHECK THE TRANSFER CASE CONTACT PLATE POSITION PIDS Connect the scan tool. Monitor the transfer case contact plate position PID. NOTE: If it is difficult to read the motor position, use the active command to energize the transfer case motor contact plate position return circuit. Switch the MSS from 2H to 4H. Mode Select Switch Position L14 L15 Contact Plate Position 1 (A) 2 (B) 3 (C) 4 (D) 2H CLOSED OPEN CLOSED CLOSED 4H OPEN CLOSED CLOSED OPEN 4L OPEN CLOSED OPEN CLOSED GO to L30. Does the transfer case contact plate PID indicate 4H? GO to L14. CHECK THE TRANSFER CASE SHIFT MOTOR OPERATION Remove the transfer case shift motor from the transfer case, leaving the wiring connector connected. Observe the transfer case shift motor while switching the MSS from 2H to 4H. GO to L30. Does the transfer case shift motor rotate from the 2H position to the 4H position? GO to L15. CHECK CIRCUITS 770 (WH), 771 (VT/YE), 772 (LB), 778 (OG) AND CIRCUIT 782 (BN/WH) FOR AN OPEN Ignition OFF. Disconnect: Transfer Case C350. Disconnect: 4x4 Module (PCM) C175t. Measure the resistance of the following circuits between 4x4 module (PCM) C175t, harness side and transfer case C350, harness side:

308-07A-22 DIAGNOSIS AND TESTING 308-07A-22 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L15 CHECK CIRCUITS 770 (WH), 771 (VT/YE), 772 (LB), 778 (OG) AND CIRCUIT 782 (BN/WH) FOR AN OPEN Circuit C175t C350 770 (WH) 6 5 771 (VT/YE) 7 1 772 (LB) 8 9 778 (OG) 9 13 782 (BN/WH) 46 10 L16 GO to L16. REPAIR the circuit. CLEAR the DTC(s). Are the resistances less than 5 ohms? REPEAT the self-test. CHECK CIRCUITS 770 (WH), 771 (VT/YE), 772 (LB), 778 (OG) AND CIRCUIT 782 (BN/WH) FOR A SHORT TO VOLTAGE Measure the voltage between the following circuits at 4x4 module (PCM) C175t, harness side and ground: Circuit Pin 770 (WH) 6 771 (VT/YE) 7 772 (LB) 8 778 (OG) 9 782 (BN/WH) 46 REPAIR the circuit. CLEAR the DTC(s). REPEAT the self-test. Is voltage present? GO to L17.

308-07A-23 DIAGNOSIS AND TESTING 308-07A-23 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L17 CHECK CIRCUITS 770 (WH), 771 (VT/YE), 772 (LB), 778 (OG) AND CIRCUIT 782 (BN/WH) FOR A SHORT TO GROUND Measure the resistance between the following circuits at 4x4 module (PCM) C175t, harness side and ground: Circuit Pin 770 (WH) 6 771 (VT/YE) 7 772 (LB) 8 778 (OG) 9 782 (BN/WH) 46 L18 GO to L18. REPAIR the circuit. CLEAR the DTC(s). Are the resistances greater than 10,000 ohms? REPEAT the self-test. CHECK THE SHIFT MOTOR FOR AN INTERNAL SHORT TO GROUND Measure the resistance between shift motor C350 pins 1, 5, 9, 10, 13 component side and ground. L19 GO to L19. INSTALL a new transfer case shift motor. CLEAR the DTC(s). REPEAT the self-test, Is the resistance greater than 10,000 ohms? then GO to L29. CHECK CIRCUITS 785 (BK/LG) AND 786 (RD) FOR POWER DURING ACTIVE COMMANDS Enter the active command mode on the diagnostic tool.

308-07A-24 DIAGNOSIS AND TESTING 308-07A-24 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L19 CHECK CIRCUITS 785 (BK/LG) AND 786 (RD) FOR POWER DURING ACTIVE COMMANDS Enter the clockwise transfer case shift motor relay active command ON and OFF and measure the voltage between transfer case C350-15, circuit 786 (RD), harness side and ground. Enter the counterclockwise transfer case shift motor relay active command ON and OFF and measure the voltage between transfer case C350-14, circuit 785 (BK/LG), harness side and ground. L20 INSTALL a new transfer case shift motor. CLEAR the DTC(s). REPEAT the self-test, then GO to L29. Are the voltages 9 volts or greater on the circuit being commanded? GO to L20. CHECK THE CW/CCW RELAY CIRCUITS FOR VOLTAGE Ignition OFF. Disconnect: Clockwise (CW) Relay C1129. Disconnect: Counterclockwise (CCW) Relay C1173. Measure the voltage between CW motor relay C1129-86 and 87, circuit 704 (DG/LG), harness side and ground. GO to L21. Measure the voltage between CCW motor relay C1173-86 and 87, circuit 704 (DG/LG), harness side and ground. REPAIR the circuit. CLEAR the DTC(s). Is the voltage 9 volts or greater? REPEAT the self-test.

308-07A-25 DIAGNOSIS AND TESTING 308-07A-25 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L21 CHECK THE CW/CCW RELAY GROUND CIRCUITS Measure the resistance between CW motor relay C1129-87a, circuit 57b (BK), harness side and ground. L22 GO to L22. Measure the resistance between CCW motor relay C1173-87a, circuit 57a (BK), harness side and ground. REPAIR the circuit. CLEAR the DTC(s). Is the resistance less than 5 ohms? REPEAT the self-test. CHECK CW/CCW RELAY CONTROL CIRCUITS Using the diagnostic tool active commands, command the motor to CW (low to high) and CCW (high to low). L23 Measure the resistance between CW relay C1129-85, circuit 975 (BN/YE) and ground; and between CCW relay C1173-85, circuit 976 (OG) and ground when commanded to move CW (low to high) or CCW (high to low). Is pin 1 of the appropriate relay grounded (5 ohms or less GO to L23. resistance) when the shift motor is commanded to move in that direction? GO to L26. CHECK CIRCUIT 785 (BK/LG) AND CIRCUIT 786 (RD) FOR AN OPEN Ignition OFF. Disconnect: CW Motor Relay C1129. Disconnect: CCW Motor Relay C1173.

308-07A-26 DIAGNOSIS AND TESTING 308-07A-26 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L23 CHECK CIRCUIT 785 (BK/LG) AND CIRCUIT 786 (RD) FOR AN OPEN Measure the resistance between transfer case C350-14, circuit 785 (BK/LG), harness side and CCW motor relay C1173-30, circuit 785 (BK/LG), harness side; and between transfer case C350-15, circuit 786 (RD), harness side and clockwise motor relay C1129-30, circuit 786 (RD), harness side. L24 GO to L24. REPAIR the circuit. CLEAR the DTC(s). Are the resistances less than 5 ohms? REPEAT the self-test. CHECK CIRCUIT 785 (BK/LG) AND CIRCUIT 786 (RD) FOR SHORT TO POWER Ignition ON. Measure the voltage between transfer case C350-14, circuit 785 (BK/LG), harness side and ground; and between transfer case C350-15, circuit 786 (RD), harness side and ground. L25 REPAIR the circuit. CLEAR the DTC(s). REPEAT the self-test. Is voltage present? GO to L25. CHECK CIRCUIT 785 (BK/LG) AND CIRCUIT 786 (RD) FOR SHORT TO GROUND Ignition OFF.

308-07A-27 DIAGNOSIS AND TESTING 308-07A-27 PINPOINT TEST L: THE VEHICLE DOES NOT SHIFT BETWEEN 2WD AND 4WD MODES CORRECTLY L25 CHECK CIRCUIT 785 (BK/LG) AND CIRCUIT 786 (RD) FOR SHORT TO GROUND Measure the resistance between transfer case C350-14, circuit 785 (BK/LG), harness side and ground; and between the transfer case C350-15, circuit 786 (RD), harness side and ground. L26 INSTALL a new relay. CLEAR the DTC(s). REPEAT the self-test. REPAIR the circuit. CLEAR the DTC(s). Are the resistances greater than 10,000 ohms? REPEAT the self-test. CHECK THE RELAY CONTROL CIRCUIT 975 (BN/YE) AND CIRCUIT 976 (OG) FOR AN OPEN Disconnect: 4x4 Module (PCM) C175b. Measure the resistance between 4x4 module (PCM) C175b-14, circuit 975 (BN/YE), harness side and CW motor relay C1129-85, circuit 975 (BN/YE), harness side; and between 4x4 module (PCM) C175b-15, circuit 976 (OG), harness side and counterclockwise motor relay C1173-85, circuit 976 (OG), harness side. L27 GO to L27. REPAIR the circuit. CLEAR the DTC(s). Are the resistances less than 5 ohms? REPEAT the self-test. CHECK CIRCUIT 975 (BN/YE) AND CIRCUIT 976 (OG) FOR A SHORT TO GROUND Ignition OFF.