Service Information

Captiva

DTC P0504

Circuit Description

The powertrain control module (PCM) monitors the brake lamp switch signal circuit and the cruise control release signal circuit every 100 ms. The PCM monitors the status of the brake lamp switch signal circuit and the cruise control signal circuit to see if they match when the brake pedal is pressed or released.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0504 Brake Switch Circuit 1-2 Correlation

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The status of the brake lamp switch input to the PCM and the cruise/brake switch input to the PCM do not match for at least 2 seconds continuously, for 10 occurrences. Each time the signals match, then do not match at 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 PCM 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 brake lamp switch input to the PCM and the cruise/brake switch 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.

Step	Action	Yes	No
*Schematic Reference:* Exterior Lamps Schematics and Cruise Control Schematics *Connector End View Reference:* Master Electrical Component List
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	With the scan tool, observe the Brake Switch parameter and the Cruise Brake Switch parameter. Press and release the brake pedal. Does the Brake Switch parameter and the Cruise Brake Switch parameter display change closely with each other?	Go to Diagnostic Aids	Go to Step 3
3	With the scan tool, observe the Cruise Brake Switch parameter. Press and release the brake pedal. Does the Cruise Brake Switch parameter display change with the brake pedal position?	Go to Step 6	Go to Step 4
4	Turn OFF the ignition. Disconnect the cruise/brake switch. Turn ON the ignition, with the engine OFF. Does the Cruise Brake Switch parameter display Applied?	Go to Step 5	Go to Step 12
5	Turn OFF the ignition. Connect a 10-amp fused jumper between the ignition positive voltage circuit of the cruise brake switch and the cruise control release signal circuit of the cruise brake switch. Turn ON the ignition, with the engine OFF. Does the Cruise Brake Switch parameter display Released?	Go to Step 16	Go to Step 8
6	Turn OFF the ignition. Disconnect the brake lamp switch. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Brake Switch parameter. Does the Brake Switch parameter display Released?	Go to Step 7	Go to Step 10
7	Turn OFF the ignition. Connect a 15-amp fused jumper between the battery positive voltage circuit of the brake lamp switch and the brake lamp switch signal circuit. Turn ON the ignition, with the engine OFF. Does the Brake Switch parameter display Applied?	Go to Step 15	Go to Step 11
8	Test the ignition positive voltage circuit of the cruise/brake switch for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 20	Go to Step 9
9	Test for an open, high resistance, or short to ground in the cruise control release signal circuit of the cruise/brake switch. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 20	Go to Step 14
10	Test the brake 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 20	Go to Step 14
11	Test the battery positive voltage circuit of the brake lamp switch for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 20	Go to Step 13
12	Test the cruise control release signal circuit of the cruise/brake switch for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 20	Go to Step 17
13	Test the brake lamp switch signal circuit for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 20	Go to Step 14
14	Inspect for poor connections at the wiring harness plug 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 20	Go to Step 17
15	Inspect for poor connections at the wiring harness plug of the cruise/brake switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 20	Go to Step 18
16	Inspect for poor connections at the wiring harness plug of the brake lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	Go to Step 20	Go to Step 19
17	Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?	Go to Step 20	-
18	Replace the brake lamp switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement?	Go to Step 20	-
19	Replace the cruise/brake switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement?	Go to Step 20	-
20	Use the scan tool in order to clear the DTCs. 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