P0504

P0504-BRAKE SWITCH 1/2 CORRELATION





For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
Ignition on.

- Set Condition:
When the PCM recognizes Brake Switch 1 and 2 do not correlate. Two Trip Fault. Three Global Good Trips to Clear.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.

Diagnostic Test

1. ACTIVE DTC
NOTE: Verify battery voltage is greater than 10 volts.

Start the engine.
Allow the engine to reach normal operating temperature.
With a scan tool, select View DTCs.

NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Is the DTC Active or Pending at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Checking for an Intermittent DTC.

2. STOP LAMP SWITCH
Turn the ignition off.
Remove the Stop Lamp Switch and disconnect the harness connector.
Measure the resistance between the (Z902) Ground circuit terminal and the (B84) Brake Signal 1 terminal in the Stop Lamp Switch.
Measure the resistance between the (F202) Fused Ignition Switch circuit terminal and the (B86) Brake Signal 2 terminal in the Stop Lamp Switch.
Apply and release the stop lamp switch plunger while monitoring the ohmmeter.
Does the resistance change from below 5.0 ohms to an open circuit?

Yes

- Go To 3

No

- Replace the Stop Lamp Switch.
- Perform the PCM Verification Test. PCM Verification Test.

3. (B84) BRAKE SIGNAL 1 CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Disconnect the C4 PCM harness connector.
Measure the resistance between ground and the (B84) Brake Signal 1 circuit in the Stop Lamp Switch harness connector.
Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (B84) Brake Signal 1 circuit.
- Perform the PCM Verification Test.PCM Verification Test.

No

- Go To 4

4. (B84) BRAKE SIGNAL 1 CIRCUIT OPEN




Measure the resistance of the (B84) Brake Signal 1 circuit from the Stop Lamp Switch harness connector to the C4 PCM harness connector.
Is the resistance below 5.0 ohms?

Yes

- Go To 5

No

- Repair the open in the (B84) Brake Signal 1 circuit.
- Perform the PCM Verification Test.PCM Verification Test.

5. (B86) BRAKE SIGNAL 2 CIRCUIT OPEN




Measure the resistance of the (B86) Brake Signal 2 circuit from the Stop Lamp Switch harness connector to the C4 PCM harness connector.
Is the resistance below 5.0 ohms?

Yes

- Go To 6

No

- Repair the open in the (B86) Brake Signal 2 circuit.
- Perform the PCM Verification Test.PCM Verification Test.

6. (B86) BRAKE SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE




Measure the voltage on the (B86) Brake Signal 2 circuit at the Stop Lamp Switch harness connector.
Turn the ignition on.
Is there any voltage present?

Yes

- Go To 7

No

- Repair the short to voltage in the (B86) Brake Signal 2 circuit.
- Perform the PCM Verification Test.PCM Verification Test.

7. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module connectors.
Search for any Technical Service Bulletins that may apply.
Were there any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test.PCM Verification Test.

No

- Replace and program the Powertrain Control Module.
- Perform the PCM Verification Test. PCM Verification Test.