Diagnostics
If you just installed the new sensor and have rear wheels turning off center when they should be centered verify you did the following upon install:
- You had all 4 wheels straight and steering wheel centered before you keyed on the ignition for the first time?
- You cycled the ignition on/off 3 times leaving it in 2WS mode before starting.
Fundamentals
Goood to know: Diagnostics – Before you open the toolbox
OEM DIAGNOSTIC INFORMATION AND PROCEDURES
Know your systems mechanical functionality. GM’s rear steer fail-safe is controlled by 70 belleville washers and stacked wave disc springs that pulls the rear wheels straight when kicked into 2WS mode. If this is binding it can set erroneous trouble codes leading one to chase phantom electrical issues.
Diagnostic Trouble Codes
Some 2003 trucks are similar to the 2002 system and others are similar to the 2004-05 system.
2002 – 2003
Ground Circuits
The manual states all models in each class have the same grounds and we know that’s a little out of reach so if you find an issue with these please email me specifics and I’d be happy to keep digging.
Click on the text to open in new window or click ‘Download’ button to download.
2002 – 2003 2003 – 2006
Resources
http://www.denalitrucks.com/documents.htm
What else can we learn today…
Rear Position Sensor Voltages. This chart shows voltage levels on pins B and D (POS1 = grn & POS2 = blu) based on steering wheel position. If your bench testing the sensor the maximum angle it turns is 360 degrees each direction. Attach 5 volts to pin A (wht) and ground to pin C (brn), then turn the hub to compare voltage levels. Turning it farther than that can damage OEM sensors. There is more information on diagnosing this sensor on DTC C0522. The voltage levels are the same for OEM and our Goood sensors however the resistance checks are only useful with the OEM sensor.
