GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The TCC Brake switch is a normally closed switch. When the TCC Brake switch is closed, (brake pedal released) the PCM senses ignition voltage on the TCC Brake switch signal circuit.

If the PCM senses a voltage on the TCC Brake switch signal circuit when the TCC Brake switch should be open, this DTC sets.

Conditions for Running the DTC

    • The engine speed is greater than 700 RPM.
    • The engine operates for greater than 2 seconds.
    • The wheel speed is greater than 48 km/h (30 mph) in order to enable the diagnostic. The diagnostic disables when the wheel speed is below 16 km/h (10 mph).

Conditions for Setting the DTC

    • The PCM detects voltage on the TCC Brake switch circuit when the TCC Brake switch should be open.
    • All above conditions are present for 1.5 seconds.

Action Taken When the DTC Sets

    • The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

Conditions for Clearing the DTC

    • A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
    • A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Use a scan tool in order to clear the DTC.

Diagnostic Aids

Important: 

   • Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
   • For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616 . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

    • Test drive the vehicle if a switch or circuit condition cannot be located. An intermittent condition may be duplicated during a test drive.
    • For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. This step determines if the fault is present.

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

1

Did you perform A Diagnostic System Check - Cruise Control?

Go to Step 2

Go to Diagnostic System Check - Cruise Control

2

  1. Connect a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Monitor the TCC Brake switch parameter in the PCM data list.

Does the brake switch parameter indicate Applied?

Go to Step  3

Go to Diagnostic Aids

3

  1. Turn OFF the ignition.
  2. Disconnect the TCC Brake switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the TCC Brake switch parameter in the PCM data list.

Does the TCC Brake switch parameter indicate Released?

Go to Step  5

Go to Step  4

4

Test the TCC Brake switch signal circuit for a short to voltage.

Did you find and correct the condition?

Go to Step  10

Go to Step  7

5

Inspect the TCC Brake switch for proper adjustment.

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the TCC Brake switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step  10

Go to Step 9

8

Replace the TCC Brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the repair?

Go to Step 10

--

9

Important: Program the replacement PCM. Refer to Powertrain Control Module Programming in Engine Controls 4.3 L, Powertrain Control Module Programming in Engine Controls 4.8 L, 5.3 L, 6.0 L, or Powertrain Control Module Programming in Engine Controls 8.1 L.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls 4.3 L, Powertrain Control Module Replacement in Engine Controls 4.8 L, 5.3 L, 6.0 L, or Powertrain Control Module Replacement in Engine Controls 8.1 L.

Did you complete the replacement?

Go to Step 10

--

10

  1. Use a 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