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.

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?

Yes : GO to U2.

No : GO to U4.
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?

Yes : REFER to the Transfer Case Control Module (TCCM) DTC Chart in this article for diagnosis.

No : GO to U3.
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?

Yes : GO to Pinpoint Test P .

No : GO to Pinpoint Test V .
U4 CHECK AUTO MODE OPERATION
- Switch the MSS to 4A mode.
Is the 4X4 auto (4A) mode indicator on in the IC message center?

Yes : GO to U7.

No : GO to U5.
U5 CHECK FOR DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self-Test - TCCM .
Are DTCs present?

Yes : REFER to the Transfer Case Control Module (TCCM) DTC Chart in this article for diagnosis.

No : GO to U6.
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?

Yes : GO to U7.

No : GO to U8.
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?

Yes : GO to U8.

No : GO to U9.
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?

Yes : GO to U9.

No : CHECK the transfer case. REFER to TRANSFER CASE .
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)?

Yes : GO to U10.

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.
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 ?

Yes : GO to U11.

No : CHECK the APP sensor and/or the PCM. REFER to the ENGINE CONTROLS - INTRODUCTION (EXCEPT DIESEL & HYBRID) (SECTION 0)
U11 CHECK 4H MODE OPERATION
- Switch the MSS to 4H mode.
Does the 4X4 (4H) indicator illuminate in the IC message center correctly?

Yes : GO to U14.

No : GO to U12.
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?

Yes : REFER to the Transfer Case Control Module (TCCM) DTC Chart in this article for diagnosis.

No : GO to U13.
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?

Yes : GO to Pinpoint Test Q .

No : GO to Pinpoint Test O .
U14 CHECK FOR STRAIGHTLINE WIND-UP IN 4H MODE
- Drive the vehicle on a dry, hard surface.
Is straightline wind-up present?

Yes : GO to Pinpoint Test S .

No : GO to U15.
U15 CHECK WIND-UP IN TURNS IN 4H MODE
- Drive the vehicle in 4H mode while turning.
Is wind-up present in turns?

Yes : GO to U16.

No : GO to Pinpoint Test O .
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?

Yes : GO to U19.

No : GO to U17.
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?

Yes : REFER to the Transfer Case Control Module (TCCM) DTC Chart in this article for diagnosis.

No : GO to U18.
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?

Yes : GO to Pinpoint Test V .

No : GO to Pinpoint Test P .
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?

Yes : GO to U20.

No : CHECK for TCCM DTCs. REFER to the Inspection and Verification procedure in this article. If no DTCs are present, GO to Pinpoint Test P .
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?

Yes : GO to U21.

No : GO to U23.
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?

Yes : REFER to the Transfer Case Control Module (TCCM) DTC Chart in this article for diagnosis.

No : GO to U22.
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?

Yes : GO to Pinpoint Test P .

No : GO to Pinpoint Test V .
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?

Yes : REFER to TRANSFER CASE .

No : GO to U24.
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?

Yes : GO to Pinpoint Test N .

No : GO to U25.
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?

Yes : CHECK the IWE and related components for leaks. GO to Pinpoint Test N .

No : GO to U26.
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?

Yes : The 4WD system is functioning correctly.

No : GO to Pinpoint Test Q .