Pinpoint Test W: The Transfer Case Jumps Out Of Gear
Four Wheel Drive (4WD) Systems - Electronic Shift
Pinpoint Tests
Pinpoint Test W: The Transfer Case Jumps Out of Gear
Normal Operation
Once the Four-Wheel Drive (4WD) system engages the user selected mode, that mode should be maintained. If the 4WD system does not stay in the selected position systematically check the 4WD system components.
This pinpoint test is intended to diagnose the following:
- Integrated Wheel Ends (IWEs) vent line(s)
- Mode Select Switch (MSS)
- Transfer case
PINPOINT TEST W: THE TRANSFER CASE JUMPS OUT OF GEAR
WARNING: When directed to drive the vehicle as part of this test, drive the vehicle on a hard surface in an area without traffic to prevent a crash. Failure to follow these instructions may result in personal injury.
-------------------------------------------------
W1 CHECK FOR OBSTRUCTED IWE VENT LINES
- With the vehicle in NEUTRAL, position it on a hoist. Refer to Vehicle Jacking and Lifting.
- NOTE: The IWE vent port is the smaller of the 2 vacuum ports.
- Disconnect the LH IWE line from the vent port.
- Attach a vacuum pump to the IWE vent line and attempt to hold a vacuum.
- Disconnect the RH IWE line from the vent port.
- Attach a vacuum pump to the IWE vent line and attempt to hold a vacuum.
- Can a vacuum be held on either IWE vent line?
Yes
INSTALL new IWE vent lines as necessary. TEST the system for normal operation.
No
GO to W2.
-------------------------------------------------
W2 VERIFY THE CONCERN
- Drive the vehicle and attempt to duplicate the concern.
- Is the concern an uncommanded range shift (in or out of low range)?
Yes
GO to W5.
No
GO to W3.
-------------------------------------------------
W3 CHECK THE MSS POSITION MONITORING THE 4WD SWITCH STATUS (4X4_SW) PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - TCCM.
- Drive the vehicle.
- Dynamically monitor the 4X4_SW PID while driving the vehicle in each shift position.
- Does the 4X4_SW PID always agree with the switch position?
Yes
GO to W4.
No
GO to Pinpoint Test T. Pinpoint Test T: The Vehicle Does Not Shift Between 2H And 4H Correctly And/Or Grinding Noise Heard During Four-Wheel Drive (4W
-------------------------------------------------
W4 CHECK FOR DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are any DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart. Transfer Case Control Module (TCCM) (DTC) Chart
No
CARRY OUT the Electronic Shift-On-The-Fly (ESOF) Functional Test. GO to Pinpoint Test AA. Pinpoint Test AA: Electronic Shift-On-The-Fly (ESOF) Functional Test
-------------------------------------------------
W5 CHECK THE 4WD INDICATORS
- Stop the vehicle.
- Transmission in NEUTRAL.
- Depress the brake pedal.
- Observe the 4WD indication in the message center while cycling through each MSS position.
- Does the 4WD indicator(s) match the MSS?
Yes
GO to W3.
No
GO to W6.
-------------------------------------------------
W6 CHECK FOR DTCs
- Transmission in PARK.
- Enter the following diagnostic mode on the scan tool: Self Test - TCCM.
- Are any DTCs present?
Yes
REFER to the Transfer Case Control Module (TCCM) DTC Chart. Transfer Case Control Module (TCCM) (DTC) Chart
No
CHECK the transfer case fluid level. If the fluid level is OK, CHECK for internal transfer case faults.
-------------------------------------------------