Diagnostic Routine E

Diagnostic Routine E

Diagnostic Overview

Vehicle Binds in a Turn or Resists Turning, Pulsates or Shudders in a Straight Line

Refer to Wiring Diagram Set 34 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

In order for the AWD (All-Wheel Drive) system to function correctly, tires and wheels must be the same size, be in good condition and the front and rear axle ratios must match. 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 4WD (Four-Wheel Drive) system in 4H (4X4 HIGH), but have no binding in turns.

Visual Inspection and Diagnostic Pre-checks

- Matching wheel/tire size, brand and tread wear

- Tire pressure

Pinpoint Test

1. CHECK FOR TORQUE AT THE REAR WHEELS

1. Ignition OFF.

2. Disconnect: ATC (Active Torque Coupling) Solenoid.

3. Drive the vehicle in a straight line on dry pavement.

Is a pulsation or shudder still present?






2. MONITOR THE AWD (All-Wheel Drive) CLUTCH CONTROL COMMANDED (AWD_CLTCH_CMD) PID (Parameter Identification)

1. Ignition OFF.

2. Connect: ATC (Active Torque Coupling) Solenoid.

3. Ignition ON.

4. Using a scan tool, view PCM (Powertrain Control Module) PIDs (Parameter Identifications).

5. Monitor the AWD (All-Wheel Drive)_CLTCH_CMD PID (Parameter Identification).

6. 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%?






3. CHECK FOR THE CORRECT WHEEL SPEEDS USING THE WHEEL SPEED SENSORS PIDs (Parameter Identifications)

1. Using a scan tool, view ABS (Anti-Lock Brake System) PIDs (Parameter Identifications).

2. While driving the vehicle at 48 km/h (30 mph), monitor the following wheel speed sensor PIDs (Parameter Identifications):

- 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?






4. MONITOR THE ACCELERATOR PEDAL POSITION (APP) PID (Parameter Identification)

1. Using a scan tool, view PCM (Powertrain Control Module) PIDs (Parameter Identifications).

2. Monitor APP PID (Parameter Identification) while applying and releasing the accelerator pedal.

Does APP PID (Parameter Identification) percent value match the approximate accelerator pedal position?






5. CHECK FOR CORRECT AWD (All-Wheel Drive) RELAY MODULE OPERATION

1. Ignition OFF.

2. Disconnect and inspect the AWD (All-Wheel Drive) relay module connector/harness and the ATC (Active Torque Coupling) solenoid connector/harness component side.

3. Repair:

- 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

4. Reconnect the AWD (All-Wheel Drive) relay module connector and the ATC (Active Torque Coupling) solenoid connector. Make sure they seat and latch correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?