Diagnostic Aids
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Inspect for poor connections at the harness connector of the rear wheel steering control module, rear wheel position sensor and the steering wheel position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
- Observe the rear wheel steering mode select switch. If all of the mode indicator LEDs are illuminated the rear wheel steering control module has lost its memory settings and the scan tool must be used to re-calibrate the rear wheel steering alignment data in the rear wheel steering control module. Refer to Measuring Wheel Alignment (w/Rear Wheel Steering) or Measuring Wheel Alignment (w/o Rear Wheel Steering) .
Steering Wheel Position Sensor - Digital Signal
- 3 outputs used (Phase A, Phase B, Index Pulse)
- Phase A & Phase B
Offset PWM wave forms created when turning the wheel
- Index pulse
Signal is present only when steering wheel is within 10 degrees either side of center
Steering Wheel Position Sensor- Analog Signal
- This is a class 2 message from the TBC
- Voltage is at or near 2.5 volts with wheels at center
- Voltage increases/decreases for less than one full turn (+/- 225 Degrees), then plateaus for the remainder of the travel