P0504

P0504

Component Location:

General Description
The Stop lamp switch is used to judge whether the acceleration system is abnormal or not. The stop lamp switch has a duplex system(signals brake test or brake light) to memorize the abnormality when the signals of depressing and releasing the brake pedal are detected simultaneously.

DTC Description
Checking output signals from both Stop lamp switch when all of them are On or OFF simultaneously, if abnormal signal is detected for more than 0.5 sec., an error is recognized. And if this condition lasts for certain period, PCM sets P0504. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC Detecting Condition:

Specification:

Schematic Diagram:

Monitor DTC Status
1. Check DTC Status
1. Connect scantool to Data Link Connector(DLC).
2. IG "ON".
3. Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F5(INFO) to check DTC's information from the DTCs menu
4. Read "DTC Status" parameter.






5. Is parameter displayed "Present fault"?

YES
a. Go to "Terminal and Connector inspection" procedure.

NO
a. Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure

NO - Go to "Power Circuit Inspection" procedure.

Power Supply Circuit Inspection
1. Voltage check
1. IG Key "OFF".
2. Disconnect the PCM connector.
3. IG Key "ON" and Brake "OFF"
4. Measure the voltage between terminal 21 of PCM harness connector and chassis ground.
5. Measure the voltage between terminal 23 of PCM harness connector and chassis ground.
6. Brake "ON"
7. Measure the voltage between terminal 21 of PCM harness connector and chassis ground.
8. Measure the voltage between terminal 23 of PCM harness connector and chassis ground.

Specification :









9. Is the measured voltage within specification ?

YES - Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

NO - Go to "Check open in harness" as follows.

2. Check open in harness
1. IG Key "OFF".
2. Disconnect the stop lamp switch and PCM connector.
3. Measure the resistance between terminal 21 of PCM harness connector and terminal 3 of stop lamp switch harness side.
4. Measure the resistance between terminal 23 of PCM harness connector and terminal 1 of stop lamp switch harness side.

Specification : Approx below 1 ohm






5. Is the measured resistance within specification ?

YES - Go to "Check voltage" procedure.

NO - Repair open in circuit and go to "Verification of Vehicle Repair" procedure.

3. Check voltage
1. IG Key "OFF".
2. Disconnect the stop lamp switch connector.
3. Measure the voltage between stop lamp switch terminal 2 and chassis ground.
4. Measure the voltage between stop lamp switch terminal 4 and chassis ground.
5. IG Key "ON".
6. Measure the voltage between stop lamp switch terminal 2 and chassis ground.
7. Measure the voltage between stop lamp switch terminal 4 and chassis ground.

Specification :









8. Is the measured voltage within specification ?

YES
- Substitute with a known - good stop lamp switch and check for proper operation.
If the problem is corrected, replace stop lamp switch and go to "Verification of Vehicle Repair" procedure.

NO
- Check the fuse between battery and stop lamp switch.
- Repair open or short in power circuit of stop lamp switch and go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Press F5(INFO) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
3. Read "DTC Status" parameter
4. Is parameter displayed "History(Not Present) fault"?

YES - System performing to specification at this time. Clear the DTC

NO - Go to the applicable troubleshooting procedure.