GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The torque converter clutch (TCC) brake switch/cruise control release signal circuit is incorporated into the stop lamp switch. The TCC brake switch/cruise control release signal circuit portion of the stop lamp switch is a normally closed switch. The stop lamp switch signal circuit portion of the stop lamp switch is a normally open switch. When the brake pedal is released, the PCM detects a high voltage signal on the TCC brake switch/cruise control release signal circuit and a low signal voltage signal on the stop lamp switch signal circuit.

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

    • When the brake pedal is released, the PCM detects a high voltage signal on the stop lamp switch signal circuit or when the PCM detects a low voltage signal on the TCC brake switch/cruise control release signal circuit.
    • The above conditions are present for 2 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

Refer to Exterior Lighting Systems Description and Operation in Lighting Systems, in order to avoid a misdiagnosis.

For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

Connector End View Reference: Cruise Control Connector End Views or Lighting Systems Connector End Views

1

Did you perform the Cruise Control Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Cruise Control

2

  1. Turn the ignition OFF.
  2. Disconnect the stop lamp switch.
  3. Turn the ignition ON, with the engine OFF.
  4. Connect a test lamp between the stop lamp switch signal circuit and a good ground.

Does the test lamp illuminate?

Go to Step 3

Go to Step 4

3

Test the stoplamp switch signal circuit for an open or for a high resistance. Refer Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

4

Test the TCC brake switch/cruise control release signal circuit for an open. Refer Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness connector of the stop lamp 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 9

Go to Step 7

6

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 9

Go to Step 8

7

Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Lighting Systems.

Did you complete the repair?

Go to Step 9

--

8

Important: Program the replacement PCM.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls 5.7 L.

Did you complete the replacement?

Go to Step 9

--

9

  1. Use a scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

Go to Step 2

System OK