Circuit Description
The TCC Brake switch contacts are normally closed contacts within the stoplamp switch. When the TCC Brake switch contacts are closed, 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 contacts 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 signal circuit when the TCC Brake switch contacts 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 a connector test adapter. Using a connector test adapter 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.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Cruise Control Schematics | |||
1 | Did you perform A Diagnostic System Check - Cruise Control? | Go to Step 2 | |
Does the brake switch parameter indicate Applied? | Go to Step 3 | Go to Diagnostic Aids | |
3 |
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 stoplamp 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 stoplamp 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 stoplamp 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 4.8L, 5.3L, 6.0L or Powertrain Control Module Programming in Engine Controls - 8.1L. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls 4.8L, 5.3L, 6.0L or Powertrain Control Module Replacement in Engine Controls - 8.1L. Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
