GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The steering wheel controls are simple momentary contact switches that connect a series of resistors so that each switch selection corresponds to a fixed resistance value. The Instrument Cluster (IPC) determines which switch has been pressed by the voltage drop across the corresponding resistance value.

Conditions for Running the DTC

This test is run every 300 milliseconds.

Conditions for Setting the DTC

The IPC receives a value that is not within the resistance value range.

Action Taken When the DTC Sets

The Instrument Cluster (IPC) will ignore the switch command.

Conditions for Clearing the MIL/DTC

The condition must be corrected.

Diagnostic Aids

    • The following may cause an intermittent:
       - A bent terminal
       - A backed out terminal
       - A damaged terminal
       - Poor terminal tension
       - A chafed wire
       - A broken wire inside the insulation
    • When diagnosing for an intermittent short or an open, massage the wire harness while watching the test equipment for changes.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step verifies that the resistance is not within the specified range. The switches operate in the 19-247 count range. The value given is the normal condition that exists when no switch is activated.

Step

Action

Value(s)

Yes

No

Schematic Reference: Steering Wheel Controls Schematics

1

Did you perform the Radio/Audio Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Radio/Audio System

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Steering Wheel Controls parameter.

Does the Steering Wheel Controls parameter indicate the specified range?

0-7 Counts

Go to Diagnostic Aids

Go to Step 3

3

Test the battery positive voltage circuit of the steering wheel control switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 6

Go to Step 4

4

Test the steering wheel controls signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 6

Go to Step 5

5

Replace the steering wheel control switches. Refer to Steering Wheel Control Switch Assembly Replacement in Steering and Column.

Did you complete the replacement?

--

Go to Step 6

--

6

  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