Pinpoint Test E: Vehicle Binds in a Turn or Resists Turning/Pulsates or Shudders in a Straight Line
Four Wheel Drive (4WD) Systems
Pinpoint Test E: Vehicle Binds in a Turn or Resists Turning/Pulsates or Shudders in a Straight Line
Normal Operation
The All-Wheel Drive (AWD) system continuously monitors vehicle conditions and automatically adjusts the torque distribution between the front and rear wheels. During normal operation, most of the torque is delivered to the front wheels. If wheel slip between the front and rear wheels is detected, or if the vehicle is under heavy acceleration, the AWD (All-Wheel Drive) system increases torque to the rear wheels to prevent or control wheel slip. When the AWD (All-Wheel Drive) system is functioning properly, there should be no perceived speed difference between the front and rear axles when launching or driving the vehicle on any uniform surface. Traction should be similar to a part time Four-Wheel Drive (4WD) system in 4H (4X4 HIGH), but have no binding in turns.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Rear axle
- Wheels/tires
- PCM
- ABS module
- 4X4 control module
PINPOINT TEST E : VEHICLE BINDS IN A TURN OR RESISTS TURNING/PULSATES OR SHUDDERS IN A STRAIGHT LINE
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.
NOTE: Carry out a thorough inspection and verification as outlined before carrying out this pinpoint test. Refer to Inspection and Verification. Four Wheel Drive (4WD) Systems
E1 CHECK FOR TORQUE AT THE REAR WHEELS
- Ignition OFF.
- Disconnect: Active Torque Coupling (ATC) Solenoid (part of rear axle) C4347.
- Drive the vehicle in a straight line on dry pavement.
Is a pulsation or shudder still present?
Yes
REFER to Differential Assembly &/or Axle Shaft Assembly &/or Drive/Propeller Shafts, Bearings and Joints for additional axle diagnosis.
No
GO to E2.
E2 MONITOR THE CLUTCH STATUS (4WDCPWMST) PID
- Ignition OFF.
- Connect: ATC (Active Torque Coupling) Solenoid C4347.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger- 4X4 Control Module.
- Monitor the 4WDCPWMST PID.
- Drive the vehicle no faster than 8 km/h (5 mph) in tight turns on dry pavement while monitoring the ATC (Active Torque Coupling) solenoid duty cycle.
Is the duty cycle greater than 20%?
Yes
GO to E3.
No
GO to Pinpoint Test F. Pinpoint Test F: DTC P1635
E3 CHECK FOR THE CORRECT WHEEL SPEEDS USING THE WHEEL SPEED SENSORS PIDs
- Enter the following diagnostic mode on the scan tool: DataLogger- 4X4 Control Module.
- While driving the vehicle at 48 km/h (30 mph), monitor the following wheel speed sensor PIDs:
- Left Front Wheel Speed Sensor (LF_WSPD)
- Left Rear Wheel Speed Sensor (LR_WSPD)
- Right Front Wheel Speed Sensor (RF_WSPD)
- Right Rear Wheel Speed Sensor (RR_WSPD)
Are all 4 wheel speeds within 2 km/h (1.2 mph) of each other?
Yes
GO to E4.
No
GO to Pinpoint Test F. Pinpoint Test F: DTC P1635
E4 MONITOR THE ACCELERATOR PEDAL POSITION (AP) PID
- Enter the following diagnostic mode on the scan tool: DataLogger- 4X4 Control Module.
- Monitor AP PID while pressing/releasing the accelerator pedal.
Does the accelerator pedal position match the PID percent value?
Yes
GO to E5.
No
REFER to Computers and Control Systems Information to diagnose the engine control system.
E5 CHECK FOR CORRECT 4X4 CONTROL MODULE OPERATION
- Disconnect: 4X4 Control Module C281.
- Disconnect: ATC (Active Torque Coupling) Solenoid C4347.
- Check the 4X4 Control Module harness and component side connectors for:
- corrosion.
- pushed-out/bent pins.
- Check the harness between the 4X4 control module and the ATC (Active Torque Coupling) solenoid.
- Connect the 4X4 control module and make sure it seats correctly.
- Connect the ATC (Active Torque Coupling) solenoid and make sure it seats correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes
INSTALL a new 4X4 control module. REFER to 4X4 Control Module . CLEAR the DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.