GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The controller area network (CAN) circuits provide a communication network between the electronic brake control module (EBCM), steering wheel position sensor, yaw rate sensor, and the data link connector (DLC).

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC U0126 CAN Steering Position Sensor Circuit Malfunction

Conditions for Running the DTC

DTC U0126 can be set anytime the ignition switch is in the ON position.

Conditions for Setting the DTC

The EBCM does not receive data from the steering wheel position sensor.

Action Taken When the DTC Sets

    • The ABS warning indicator turns ON.
    • The vehicle stability control (VSC) warning indicator turns ON.
    • The VSC and traction control is disabled.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • An open or high resistance in the steering wheel position sensor ground circuit
    • An open, high resistance, or short to ground in the steering wheel position sensor ignition voltage
    • A steering wheel position sensor malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the steering wheel position sensor ground circuit for an open or high resistance.

  2. This step tests the steering wheel position sensor ignition voltage circuit for an open, high resistance or short to ground.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Test the steering wheel position sensor ground circuit for an open or high resistance.

Did you find and correct the condition?

--

Go to Step 5

Go to Step 3

3

Test the steering wheel position sensor ignition voltage circuit for an open, high resistance, or short to ground.

Did you find and correct the condition?

--

Go to Step 5

Go to Step 4

4

Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 5

--

5

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK