Pinpoint Test E : Vehicle Binds In A Turn Or Resists Turning/Pulsates Or Shudders In A Straight Line
- WARNING: 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.
Refer to All Wheel Drive (AWD) for schematic and connector information.
Normal Operation and Fault Conditions
The AWD system is an active system, which means it not only responds to wheel slip between the front and rear axles but also has the ability to anticipate wheel slip and transfer torque to the rear wheels before the slip occurs. The AWD system is active all the time and requires no input from the operator. The 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, if the vehicle is under acceleration or if the vehicle is in a handling event, the AWD system increases and distributes torque to the rear wheels as needed. When the AWD 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 4WD system in 4H (4X4 HIGH), but have no binding in turns.
Possible Sources
- Wiring, terminals and connectors
- Wheels/tires
- ABS system
- AWD relay module
- Active Torque Coupling (ATC) Clutch
Visual Inspection and Pre-checks
- Wheel speed sensor wiring harness
- E1 CHECK FOR TORQUE AT THE REAR WHEELS
- Ignition OFF.
- Disconnect active torque coupling (ATC) solenoid C4347.
- Inspect the connector for damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals.
- Drive the vehicle in a straight line on dry pavement.
Is a pulsation or shudder still present?
Yes Refer to: Rear Drive Axle and Differential . No GO to E2 - E2 MONITOR THE CLUTCH STATUS PID
- Ignition OFF.
- Connect active torque coupling (ATC) solenoid C4347.
- Ignition ON.
- Using the diagnostic scan tool, monitor the AWD_CLTCH_CMD# PID.
- Drive the vehicle at a constant 5 mph (8 km/h) in tight turns on dry pavement while monitoring the active torque coupling (ATC) solenoid duty cycle.
Is the duty cycle greater than 20%?
Yes GO to E3 No GO to Pinpoint Test A - E3 CHECK FOR THE CORRECT WHEEL SPEEDS
- Drive the vehicle at 30 mph (48 km/h), 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 1.2 mph (2 km/h) of each other?
Yes GO to E4 No GO to Pinpoint Test B - Drive the vehicle at 30 mph (48 km/h), monitor the following wheel speed sensor PIDs:
- E4 CHECK FOR CORRECT AWD (ALL-WHEEL DRIVE) RELAY MODULE OPERATION
- Disconnect the AWD relay module C3841.
- Disconnect the active torque coupling (ATC) solenoid C4347.
- Check for the following:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Connect AWD Relay Module C3841.
- Connect Active Torque Coupling (ATC) solenoid C4347 and make sure it seats correctly.
- PERFORM the AWD Drive Cycle. Refer to: Four-Wheel Drive Systems - System Operation and Component Description . and determine if the concern is still present.
Is the concern still present?
Yes INSTALL a new AWD relay module. Refer to: All-Wheel Drive (AWD) Module . No The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.