Pinpoint Test A: 4WD (Four-Wheel Drive) System Functional Test
- Normal Operation and Fault Conditions
Refer to FOUR WHEEL DRIVE SYSTEMS for schematic and connector information. Refer to MODULE COMMUNICATION NETWORK for schematic and connector information.
In 2H mode, the AWD supplies a ground path to the IWE solenoid to apply vacuum to the IWE s (disengaging the front hubs from the front axle). In 4H or 4L modes, the AWD does not supply the ground path to the IWE solenoid, vacuum is not applied to IWE s the and an internal spring in the IWE s keeps the hubs engaged.
When operating in 4H or 4L mode, the transfer case and both IWE s are locked. When in 4L mode, the transfer case low range gear set provides an additional 2.64 gear reduction. When operating in 2H mode, the transfer case and both IWE s are unlocked.
Possible Sources
- 4WD system inputs
- Transfer case internal fault
- IWE
NOTE: 4X4 High and 4X4 Low are not intended for driving on hard/dry surfaces; using these modes while driving on these surfaces may produce noises like intermittent clunking, but will not damage driveline components. - A1 CHECK FOR CMDTC (CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE)
- Ignition ON.
- Enter the following diagnostic mode: CMDTC Self-Test.
Are any DTC related to engine torque, transmission gear, ambient temperature, TCCM communication, or transfer case operation present?
Yes RESOLVE all DTC first. No GO to A2 - A2 CHECK 2H OPERATION
- Ignition OFF.
- Switch the MSS to 2H
- Ignition ON.
Does the message center display 4X2 or 2WD for approximately 4 seconds?
Yes GO to A3 No REPAIR all message center or IPCDTC - A3 CHECK FOR WIND-UP IN 2H
- Drive the vehicle on a dry, hard surface while executing turns.
Is wind-up present in turns?
Yes GO to A4 No GO to A5 - A4 CHECK FOR TRANSFER CASE DISENGAGEMENT
- With the vehicle in NEUTRAL, position it on a hoist. Refer to the appropriate service information for the procedure.
- Rotate the rear driveshaft while observing the front driveshaft.
Does the front driveshaft rotate?
Yes Refer to the appropriate service information for the procedure. No GO to Pinpoint Test X - A5 CHECK WIND-UP IN 4H MODE
- Drive the vehicle in 4H mode while turning.
Is wind-up present in turns?
Yes GO to A7 No GO to A6 - A6 CHECK FOR TRANSFER CASE ENGAGEMENT
- MSS in 4H
- With the vehicle in NEUTRAL, position it on a hoist. Refer to the appropriate service information for the procedure.
- Rotate the rear driveshaft while observing the front driveshaft.
Does the front driveshaft rotate?
Yes GO to A7 No Refer to the appropriate service information for the procedure. - A7 CHECK 4L OPERATION
- Bring the vehicle to a stop with the transmission in NEUTRAL and switch the MSS to 4L.
- Drive the vehicle in 4L mode
Did the transfer case operate in 4L?
Yes GO to A8 No Refer to the appropriate service information for the procedure. - A8 CHECK 2H TO 4H SHIFT AT SPEED ABOVE 32 KM/H (20 MPH)
- Switch the MSS to 2H.
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NOTE: When performing 2H to 4H or 4H to 2H shift, release the accelerator pedal prior to the shift and wait until Shift in Progress disappears.
Drive the vehicle on the road and shift from 2H to 4H while driving above 32 km/h (20 mph).
Does the transfer case shift to 4H satisfactorily?
Yes The 4WD system is functioning correctly. No Refer to the appropriate service information for the procedure.