Code No.P0504: Malfunction of the Stop Lamp Switch System.
PROBABLE CAUSES
OPERATION
- For the stop lamp switch, two switches, a stop lamp switch for the stop lamp illumination and a brake switch exclusively for the cruise control system, are incorporated to improve the reliability.
- As for the stop lamp switch, when the brake pedal is depressed/released, the stop lamp switch ON/OFF signal is transmitted from the ETACS-ECU to the engine-ECU via CAN bus line.
- As for the brake switch, the engine-ECU connector terminal BRK monitor the state of the brake switch. The brake switch turn ON/OFF when the brake pedal is depressed/released, and the input signal to the engine-ECU connector terminal BRK changes. According to this change, the engine-ECU judges the state of the brake switch.
DIAGNOSIS CODE SET CONDITIONS
Check Condition
- The cruise control indicator lamp illuminates <standard meter> or the cruise control display screen is displayed <high contrast meter>.
Judgement Criteria
- Open/short in stop lamp switch circuit.
- Open circuit in the brake switch circuit (between engine-ECU connector terminal BRK and earth).
- Malfunction of CAN bus line.
PROBABLE CAUSES
- Malfunction of CAN bus system.
- Damaged harness or connector.
- Malfunction of the fuse No.14.
- Malfunction of the stop lamp switch.
- Malfunction of the ETACS-ECU.
- Malfunction of the engine-ECU.
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- If there is any problem in the CAN bus lines, an incorrect diagnosis code may be stored. Prior to this diagnosis, diagnose the CAN bus lines.
- Before replacing the ECU, ensure that the CAN bus lines is normal.
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STEP 1. Check the CAN bus system diagnosis.
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Using M.U.T.-III, perform CAN bus diagnosis (Refer to GROUP 54C - Explanation About The M.U.T-III Can Bus Diagnostics ).
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Q.
Is the check result satisfactory?
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Go to Step 2.
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Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting, Can Bus Diagnostic Table ). Then go to Step 12.
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STEP 2. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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- Item 74: Stop lamp switch
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Q.
Is the check result normal?
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Go to Step 6.
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Go to Step 3.
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STEP 3. Check the stop lamp operation.
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Check the stop lamp operation.
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OK:
Brake pedal depressed: Stop lamp will illuminate Brake pedal not depressed: Stop lamp does not illuminate
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Q.
Is the check result normal?
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Go to Step 4.
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Check the stop lamp system (Refer to GROUP 54A - Rear Combination Lamp, Symptom Procedures, Inspection Procedure 2: The stop lamps do not illuminate or go out normally ). Then go to Step 11.
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STEP 4. Check the ETACS system data list.
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Using M.U.T.-III, check the ETACS system data list (Refer to GROUP 54A - ETACS, Troubleshooting, data list reference table ).
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- Item 290: Stop lamp switch
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Q.
Is the check result normal?
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Go to Step 5.
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Replace the ETACS-ECU (Refer to GROUP 54A - ETACS, ETACS-ECU ). Then go to Step 11.
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STEP 5. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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- Item 74: Stop lamp switch
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Q.
Is the check result normal?
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Go to Step 6.
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Replace the engine-ECU (Refer to GROUP 13A - Engine-ECU <4B1>, GROUP 13B - Engine-ECU <6B3>). Then go to Step 11.
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STEP 6. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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Q.
Is the check result normal?
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Go to Step 10.
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Go to Step 7.
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STEP 7. Check the harness wire between engine-ECU connector terminal BRK and stop lamp switch connector, and between stop lamp switch connector and earth.
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- Check connector or harness wire for open/short circuit and damage.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair connector or damaged harness wire. Then go to Step 11.
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STEP 8. Check the stop lamp switch.
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Refer to GROUP 35A - Brake Pedal, Inspection, Stop Lamp Switch Check .
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Q.
Is the check result normal?
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Go to Step 9.
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Replace the stop lamp switch (Refer to GROUP 35A - Brake Pedal ). Then go to Step 11.
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STEP 9. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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Q.
Is the check result normal?
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Go to Step 10.
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Replace the engine-ECU (Refer to GROUP 13A - Engine-ECU <4B1>, GROUP 13B - Engine-ECU <6B3>). Then go to Step 11.
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STEP 10. Read the diagnosis code.
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(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system.
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(2)Turn the ignition switch to the "ON" position, and press the cruise control ON/OFF switch to turn the cruise control system to ON (the cruise control indicator lamp <standard meter> or the cruise control display screen <high contrast meter> is turned on).
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(3)With the cruise control switches not operated, depress the brake pedal for several seconds, and then read the diagnosis code of the cruise control system (Refer to ).
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Q.
Is diagnosis code No. P0504 stored?
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Replace the engine-ECU (Refer to GROUP 13A - Engine-ECU <4B1>, GROUP 13B - Engine-ECU <6B3>). Then go to Step 11.
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It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunction ).
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STEP 11. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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- Item 74: Stop lamp switch
- Item 89: Brake switch
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Q.
Is the check result normal?
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Go to Step 12.
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Return to Step 2.
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STEP 12. Read the diagnosis code.
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(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system.
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(2)Turn the ignition switch to the "ON" position, and press the cruise control ON/OFF switch to turn the cruise control system to ON (the cruise control indicator lamp <standard meter> or the cruise control display screen <high contrast meter> is turned on).
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(3)With the cruise control switches not operated, depress the brake pedal for several seconds, and then read the diagnosis code of the cruise control system (Refer to ).
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Q.
Is diagnosis code No. P0504 stored?
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Return to Step 1.
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The procedure is complete.
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