Diagnostic Aids
- Inspect for proper adjustment of the stop lamp switch. Refer to Stop Lamp Switch Adjustment .
- Check for intermittents and poor connections. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
DTC P0504
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Exterior Lights Schematics and 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 | Go to Diagnostic Starting Point - Lighting Systems in Vehicle DTC Information |
| 2 |
IMPORTANT:
The stop lamp switch must be adjusted correctly for proper operation. Refer to Stop Lamp Switch Adjustment . Check to see if the stop lamps operate correctly.Do the stop lamps operate correctly? |
Go to Step 3 | Go to Stop Lamps Inoperative |
| 3 |
|
Go to Step 6 | Go to Step 4 |
| 4 |
|
Go to Step 5 | Go to Step 6 |
| 5 | With the brake pedal released, use a digital multimeter, test for voltage between PCM connector C1 terminal 3 and the PCM connector C3 terminal 11. Refer to Circuit Testing in Wiring Systems. Is the voltage between 7.5 volts and 14 volts? |
Go to Step 6 | Go to Step 7 |
| 6 | Test for intermittent circuit problems between the brake switch and the PCM. Refer to Testing for Electrical Intermittents
and Wiring Repairs
in Wiring Systems Did you find and complete the repair? |
Go to Step 9 | Go to Step 8 |
| 7 | Repair the short or high resistance in the stop lamp signal circuit between the PCM connector C1 terminal 3 and the PCM connector C3 terminal 11. Refer to Wiring Repairs
in Wiring Systems Did you find and complete the repair? |
Go to Step 9 | Go to Step 2 |
| 8 | Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement
-LV6 or Powertrain Control Module (PCM) Replacement
- LNK in Engine Controls Did you complete the replacement? |
Go to Step 9 | Go to Step 2 |
| 9 |
|
Go to Step 2 | System OK |