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Pinpoint Test U: Four-Wheel Drive (4WD) System Functional Test

NOTE: 4X4 is not intended for driving on hard/dry surfaces; using 4X4 mode while driving on these surfaces may produce noises like intermittent clunking, but will not damage driveline components.
  1. U1 CHECK 2H MODE OPERATION 
    • Shift the transmission into the NEUTRAL position.
    • Switch the Mode Select Switch (MSS) to 2H mode.
    • Are there any 4WD mode indicators present in the Instrument Cluster (IC) message center? 
      1. Yes  : GO to U2.
      2. No  : GO to  U4.
  2. U2 CHECK FOR TCCM DTCs 
    • Shift the transmission into the PARK position.
    • Ignition ON.
    • Enter the following diagnostic mode on the scan tool: Self-Test - TCCM.
    • Are DTCs retrieved? 
      1. Yes  : REFER to the Transfer Case Control Module (TCCM) DTC Chart  in this service information for diagnosis.
      2. No  : GO to U3.
  3. U3 CHECK FOR WIND-UP IN 2H MODE 
    • Drive the vehicle on a dry, hard surface while executing turns.
    • Is wind-up present in turns? 
      1. Yes  : GO to PINPOINT TEST P .
      2. No  : GO to PINPOINT TEST V .
  4. U4 CHECK AUTO MODE OPERATION 
    • Switch the MSS to 4A mode.
    • Is the 4X4 auto (4A) mode indicator on in the IC message center? 
      1. Yes  : GO to  U7.
      2. No  : GO to U5.
  5. U5 CHECK FOR DTCs 
    • Ignition ON.
    • Enter the following diagnostic mode on the scan tool: Self-Test - TCCM.
    • Are DTCs present? 
      1. Yes  : REFER to the Transfer Case Control Module (TCCM) DTC Chart  in this service information for diagnosis.
      2. No  : GO to U6.
  6. U6 CHECK FOR WIND-UP IN 4A MODE 
    • Drive the vehicle on a dry, hard surface, executing turns while applying the throttle.
    • Is wind-up present in turns? 
      1. Yes  : GO to U7.
      2. No  : GO to  U8.
  7. U7 CHECK THE 4WD PWM CLUTCH STATUS (4WD_CLTCH_OUT) PID 
    • Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
    • Monitor the 4WD_CLTCH_OUT PID.
    • Does the PID indicate 2 to 10% clutch application at closed throttle? 
      1. Yes  : GO to U8.
      2. No  : GO to  U9.
  8. U8 CHECK FOR WIND-UP IN 4A MODE WITH 100% CLUTCH USING THE 4WD PWM CLUTCH STATUS (4WD_CLTCH_OUT) ACTIVE COMMAND 
    • Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
    • Command the 4WD_CLTCH_OUT to 100%.
    • Drive the vehicle on a dry, hard surface, executing turns.
    • Is wind-up present in turns? 
      1. Yes  : GO to U9.
      2. No  : CHECK the transfer case. REFER to TRANSFER CASE .
  9. U9 CHECK AVERAGE FRONT WHEEL SPEED (FRT_WHL_SPD) AND AVERAGE REAR WHEEL SPEED (REAR_WHL_SPD) PIDs 
    • Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
    • Monitor the FRT_WHL_SPD and REAR_WHL_SPD PIDs.
    • Drive the vehicle 30 km/h (18 mph).
    • Record and compare the FRT_WHL_SPD and REAR_WHL_SPD PIDs.
    • Do the FRT_WHL_SPD and REAR_WHL_SPD PID values match within 1.5 km/h (1 mph)? 
      1. Yes  : GO to U10.
      2. No  : VERIFY all 4 tires are the same size and brand. INSTALL new tires as necessary. If the tires are OK, CHECK the ABS. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL and VERIFY that the 4 road tire sizes match. TEST the system for normal operation.
  10. U10 CHECK THE ABSOLUTE THROTTLE POSITION (TP_TCCM) PID 
    • Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
    • Ignition ON.
    • Monitor the TP_TCCM PID.
      NOTE: The TP_TCCM PID is Accelerator Pedal Position (APP) as communicated by the PCM via High Speed Controller Area Network (HS-CAN).

      Slowly move throttle from closed throttle to Wide Open Throttle (WOT) and observe the TP_TCCM PID.

    • Does the TP_TCCM PID value vary between 0% at closed throttle and 100% at WOT? 
      1. Yes  : GO to U11.
      2. No  : CHECK the APP sensor and/or the PCM. REFER to the INTRODUCTION - GASOLINE MODELS and ENGINE CONTROLS - POWERTRAIN DTC CHARTS & DESCRIPTIONS (EXCEPT DIESEL & HYBRID) .
  11. U11 CHECK 4H MODE OPERATION 
    • Switch the MSS to 4H mode.
    • Does the 4X4 (4H) indicator illuminate in the IC message center correctly? 
      1. Yes  : GO to  U14.
      2. No  : GO to U12.
  12. U12 CHECK FOR DTCs 
    • Shift the transmission into the PARK position.
    • Enter the following diagnostic mode on the scan tool: Self-Test - TCCM.
    • Are DTCs retrieved? 
      1. Yes  : REFER to the Transfer Case Control Module (TCCM) DTC Chart  in this service information for diagnosis.
      2. No  : GO to U13.
  13. U13 CHECK FOR WIND-UP IN 4H MODE 
    • Drive the vehicle on a dry, hard surface while executing turns.
    • Is wind-up present in turns? 
      1. Yes  : GO to PINPOINT TEST Q .
      2. No  : GO to PINPOINT TEST O .
  14. U14 CHECK FOR STRAIGHTLINE WIND-UP IN 4H MODE 
    • Drive the vehicle on a dry, hard surface.
    • Is straightline wind-up present? 
      1. Yes  : GO to PINPOINT TEST S .
      2. No  : GO to U15.
  15. U15 CHECK WIND-UP IN TURNS IN 4H MODE 
    • Drive the vehicle in 4H mode while turning.
    • Is wind-up present in turns? 
      1. Yes  : GO to U16.
      2. No  : GO to PINPOINT TEST O .
  16. U16 CHECK 4L MODE OPERATION 
    • Bring the vehicle to a stop with the transmission in NEUTRAL, switch the MSS to 4L mode.
    • Does the 4WD LOW (4L) indicator in the IC message center illuminate correctly? 
      1. Yes  : GO to  U19.
      2. No  : GO to U17.
  17. U17 CHECK FOR DTCs 
    • Shift the transmission into the PARK position.
    • Enter the following diagnostic mode on the scan tool: Self-Test - TCCM.
    • Are DTCs retrieved? 
      1. Yes  : REFER to the Transfer Case Control Module (TCCM) DTC Chart  in this service information for diagnosis.
      2. No  : GO to U18.
  18. U18 CHECK FOR WIND-UP IN 4L MODE 
    • Drive the vehicle on a dry, hard surface while executing turns.
    • Is wind-up present in turns? 
      1. Yes  : GO to PINPOINT TEST V .
      2. No  : GO to PINPOINT TEST P .
  19. U19 CHECK FOR WIND-UP IN TURNS IN 4L MODE 
    • Drive the vehicle on a dry, hard surface while executing turns.
    • Is wind-up present and 4L mode functioning? 
      1. Yes  : GO to U20.
      2. No  : CHECK for TCCM DTCs. REFER to the INSPECTION AND VERIFICATION  procedure. If no DTCs are present, GO to PINPOINT TEST P .
  20. U20 CHECK 4L MODE TO 2H MODE SHIFT 
    • With the vehicle at a stop and transmission in NEUTRAL, switch the MSS from 4L mode to 2H mode.
    • Are there any 4WD mode indicators present in the IC message center? 
      1. Yes  : GO to U21.
      2. No  : GO to  U23.
  21. U21 CHECK FOR DTCs 
    • Shift the transmission into the PARK position.
    • Release the brake pedal.
    • Enter the following diagnostic mode on the scan tool: Self-Test - TCCM.
    • Are DTCs retrieved? 
      1. Yes  : REFER to the Transfer Case Control Module (TCCM) DTC Chart  in this service information for diagnosis.
      2. No  : GO to U22.
  22. U22 CHECK FOR WIND-UP IN 2H MODE 
    • Drive the vehicle on a dry, hard surface while executing turns.
    • Is wind-up present in turns? 
      1. Yes  : GO to PINPOINT TEST P .
      2. No  : GO to PINPOINT TEST V .
  23. U23 CHECK FOR TRANSFER CASE DISENGAGEMENT 
    • With the vehicle in NEUTRAL, position it on a hoist. Refer to JACKING & LIFTING .
    • Rotate the rear driveshaft while observing the front driveshaft.
    • Does the front driveshaft rotate? 
      1. Yes  : REFER to TRANSFER CASE .
      2. No  : GO to U24.
  24. U24 CHECK FOR LH AND RH IWE DISENGAGEMENT 
    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 LF tire one revolution forward and one revolution backward while observing the LF halfshaft and U-joint.
    • Rotate the RF tire one revolution forward and one revolution backward while observing the RF halfshaft and U-joint.
    • Does the LH or RH front halfshaft rotate? 
      1. Yes  : GO to PINPOINT TEST N .
      2. No  : GO to U25.
  25. U25 CHECK FOR IWE VACUUM LEAKS 
    • Ignition OFF.
    • Disconnect both vacuum lines from the IWE solenoid.
    • Using a hand vacuum pump, apply 508 mm (20 in) Hg of vacuum to the IWE apply vacuum circuit.
    • Observe the vacuum reading.
    • Did the vacuum drop more than 25 mm (1 in) Hg per minute? 
      1. Yes  : CHECK the IWE and related components for leaks. GO to PINPOINT TEST N .
      2. No  : GO to U26.
  26. U26 CHECK 2H MODE TO 4H MODE SHIFT AT SPEED ABOVE 32 KM/H (20 MPH) 
    • Switch the MSS to 2H mode.
    • Drive the vehicle on the road and shift from 2H mode to 4H mode while driving above 32 km/h (20 mph).
    • Does the transfer case shift to 4H mode satisfactorily? 
      1. Yes  : The 4WD system is functioning correctly.
      2. No  : GO to PINPOINT TEST Q .
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