Pinpoint Test F: Four-Wheel Drive (4WD) System Jumps Out of Gear

Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand

Pinpoint Tests

Pinpoint Test F: Four-Wheel Drive (4WD) System 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 End (IWE) vent line(s)
- Mode Select Switch (MSS)
- Transfer case



PINPOINT TEST F: THE FOUR-WHEEL DRIVE (4WD) SYSTEM JUMPS OUT OF GEAR

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F1 CHECK FOR OBSTRUCTED IWE VENT LINES


- With the vehicle in NEUTRAL, position in on a hoist. Refer to Maintenance/Service and Repair.
- NOTE: The IWE vent port is the smaller of the 2 vacuum ports.
- Disconnect the LH IWE line from the vent port.
- Attach a hand vacuum pump to the IWE vent line.
- Attempt to draw and hold a vacuum.
- Connect LH IWE line.
- Disconnect the RH IWE line from the vent port.
- Attempt to draw and 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 F2.

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F2 CHECK THE MSS POSITION PIDs


- Ignition OFF.
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - 4X4 Control Module.
- Drive the vehicle.
- Dynamically monitor the 4WDINP_SW PID while driving the vehicle in each MSS position.





- Does the 4WDINP_SW PID always agree with the MSS position?

Yes
GO to F4.

No
Go To Pinpoint Test D. Pinpoint Test D: the Vehicle Does Not Shift Between 4X4 Auto and 4X4 Modes Correctly

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F3 CHECK FOR DTCs


- Carry out the on-demand self-test.

- Are DTCs present?

Yes
REFER to the 4X4 Control Module DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand

No
Go To Pinpoint Test I. Pinpoint Test I: the Vehicle Has No Torque or Inadequate Torque at Rear Wheels In 4X4 Auto Mode

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F4 CHECK THE 4WD INDICATORS


- Apply the brakes and stop the vehicle.
- Shift the transmission into the NEUTRAL position.
- Observe the 4WD indicators in the Instrument Cluster (IC) while cycling through each MSS position.

- Do the 4WD indicators match MSS switch positions?

Yes
GO to F3.

No
GO to F5.

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F5 CHECK FOR DTCs


- Shift the transmission into the PARK position.
- Carry out the on-demand self-test.

- Are DTCs present?

Yes
REFER to the 4X4 Control Module DTC Chart for diagnosis. Four Wheel Drive (4WD) Systems - 1-Speed Torque-On-Demand

No
CHECK the transfer case fluid level. If the fluid level is OK, CHECK for internal transfer case faults. TEST the system for normal operation.

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