Circuit Description
The engine control module (ECM) monitors the stop lamp switch signal circuit and the torque converter clutch (TCC) brake switch/cruise control release signal circuit every 100 ms. The ECM monitors the status of the stop lamp switch signal circuit and the TCC brake switch/cruise control signal circuit to see if they match when the brake pedal is pressed or released.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
The status of the stop lamp switch input to the ECM, and the TCC brake switch/cruise control input to the ECM do not match for at least 2 seconds continuously, for 10 occurrences. Each time the signals match then do not match a counter increments. When the counter reaches 10 the DTC will set.
Action Taken When the DTC Sets
When DTC P0504 is set the following will occur:
| • | The cruise control is disabled. |
| • | The ECM will function as if the brake pedal is not pressed. |
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
Conditions for Clearing the DTC
| • | The DTC will clear when the status of the stop lamp switch input to the ECM, and the TCC brake switch/cruise control input to the ECM match for at least 2 seconds continuously for both the pressed position and the released position. |
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
| • | Inspect for proper adjustment of the TCC/cruise control release switch, if equipped with automatic Transmission. Refer to Torque Converter Clutch/Cruise Control Release Switch Adjustment in Automatic Transmission - 5L40-E. |
| • | Inspect for proper adjustment of the stop lamp switch. Refer to Stop Lamp Switch Adjustment . |
| • | Check for internments and poor connections. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics and Cruise Control Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Lighting Systems Diagnostic System Check? | Go to Step 2 | |
2 |
Important: The stop lamp switch and the TCC/cruise control release switch must be adjusted correctly for proper operation. Refer to Stop Lamp Switch Adjustment and Torque Converter Clutch/Cruise Control Release Switch Adjustment in Automatic Transmission - 5L40-E.
Does the Stoplamp Pedal Switch parameter and Cruise Release Brake Pedal Switch parameter display change closely with each other? | Go to Diagnostic Aids | Go to Step 3 |
3 |
Does the Cruise Release Brake Pedal Switch parameter display change with the brake pedal position? | Go to Step 6 | Go to Step 4 |
4 |
Does the Cruise Release Brake Pedal Switch parameter display released? | Go to Step 5 | Go to Step 12 |
5 |
Does the Cruise Release Brake Pedal Switch parameter display applied? | Go to Step 15 | Go to Step 8 |
6 |
Does the Stoplamp Pedal Switch parameter display OFF? | Go to Step 7 | Go to Step 10 |
7 |
Does the Stoplamp Pedal Switch parameter display ON? | Go to Step 16 | Go to Step 11 |
8 | Test the ignition 1 voltage circuit of the TCC/cruise control switch for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 9 |
9 | Test for an open or short to ground in the signal circuit of the TCC/cruise control switch. Refer to Circuit Testing and Wiring Repairs n Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 14 |
10 | Test the stop lamp switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 14 |
11 | Test the battery positive voltage circuit of the stop lamp switch for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 13 |
12 | Test the TCC/cruise control switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 17 |
13 | Test the stop lamp switch signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 14 |
14 | Inspect for poor connections at the harness connector of the ECM. 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 20 | Go to Step 17 |
15 | Inspect for poor connections at the harness connector of the TCC/cruise control release 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 20 | Go to Step 18 |
16 | 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 20 | Go to Step 19 |
17 |
Important: Program the replacement ECM. Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls 2.6L and 3.2L. Did you complete the replacement? | Go to Step 20 | -- |
18 | Replace the TCC/cruise control release switch. Refer to Torque Converter Clutch/Cruise Control Release Switch Replacement in Automatic Transmission 5L40-E. Did you complete the replacement? | Go to Step 20 | -- |
19 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 20 | -- |
20 |
Does the DTC reset? | Go to Step 2 | System OK |
