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 engine control module (ECM) 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.
This diagnostic procedure supports the following DTC:
DTC P0571 (6.6L) Cruise Control Brake Switch Circuit
| • | 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). | 
| • | When the brake pedal is released, the ECM detects a high voltage signal on the stop lamp switch signal circuit or when the ECM detects a low voltage signal on the TCC brake switch/cruise control release signal circuit. | 
| • | The above conditions are present for 2 seconds. | 
| • | The ECM stores the DTC information into memory when the diagnostic runs and fails. | 
| • | The malfunction indicator lamp (MIL) will not illuminate. | 
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. | 
| • | 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. | 
| • | Refer to Exterior Lighting Systems Description and Operation in order to avoid a misdiagnosis. | 
| • | For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections . | 
Step  | Action  | Yes  | No  | 
|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Lighting Systems Connector End Views  | |||
1  | Did you perform the Diagnostic System Check - Vehicle?  | Go to Step 2  | |
2  | 
 Does the test lamp illuminate?  | Go to Step 3  | Go to Step 4  | 
3  | Test the stop lamp switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | Go to Step 9  | Go to Step 6  | 
4  | Test the torque converter clutch (TCC) brake switch/cruise control release signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs . 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 . 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 engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 . Did you complete the repair?  | Go to Step 9  | --  | 
8  | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?  | Go to Step 9  | --  | 
9  | 
 Does the DTC reset?  | Go to Step 2  | System OK  | 
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 engine control module (ECM) 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.
This diagnostic procedure supports the following DTC:
DTC P0571 (7.8L) Cruise Control Brake Switch Circuit
| • | The ignition is ON. | 
| • | The traction control system (TCS) or the antilock brake system (ABS) have not failed. | 
| • | When the brake pedal is released, the ECM detects a high voltage signal on the stop lamp switch signal circuit or when the ECM detects a low voltage signal on the TCC brake switch/cruise control release signal circuit. | 
| • | The above conditions are present for 1.5 seconds. | 
| • | The ECM stores the DTC information into memory when the diagnostic runs and fails. | 
| • | The malfunction indicator lamp (MIL) will not illuminate. | 
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. | 
| • | 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. | 
| • | Refer to Exterior Lighting Systems Description and Operation in order to avoid a misdiagnosis. | 
| • | For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections . | 
Step  | Action  | Yes  | No  | 
|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Lighting Systems Connector End Views  | |||
1  | Did you perform the Diagnostic System Check - Vehicle?  | Go to Step 2  | |
2  | 
 Does the test lamp illuminate?  | Go to Step 3  | Go to Step 4  | 
3  | Test the stop lamp switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | Go to Step 9  | Go to Step 6  | 
4  | Test the torque converter clutch (TCC) brake switch/cruise control release signal circuit for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs . 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 . 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 engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 . Did you complete the repair?  | Go to Step 9  | --  | 
8  | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?  | Go to Step 9  | --  | 
9  | 
 Does the DTC reset?  | Go to Step 2  | System OK  | 
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 powertrain control module (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.
This diagnostic procedure supports the following DTC:
DTC P0571 (8.1L) Cruise Control Brake Switch Circuit
| • | 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). | 
| • | 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. | 
| • | 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. | 
| • | 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. | 
| • | Refer to Exterior Lighting Systems Description and Operation in order to avoid a misdiagnosis. | 
| • | For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections . | 
Step  | Action  | Yes  | No  | 
|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Lighting Systems Connector End Views  | |||
1  | Did you perform the Diagnostic System Check - Vehicle?  | Go to Step 2  | |
2  | 
 Does the test lamp illuminate?  | Go to Step 3  | Go to Step 4  | 
3  | Test the stop lamp switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | Go to Step 9  | Go to Step 6  | 
4  | Test the torque converter clutch (TCC) brake switch/cruise control release signal circuit for an open. Refer to Circuit Testing and Wiring Repairs . 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 . 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 powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 . Did you complete the repair?  | Go to Step 9  | --  | 
8  | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?  | Go to Step 9  | --  | 
9  | 
 Does the DTC reset?  | Go to Step 2  | System OK  |