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DTC P0504: Malfunction of the Stoplight Switch System
 
 
 
 
OPERATION
  • For the stoplight switch, two switches, a stoplight switch for the stoplight illumination and a brake switch exclusively for the cruise control system, are incorporated to improve the reliability.
  • As for the stoplight switch, when the brake pedal is depressed/released, the stoplight switch ON/OFF signal is transmitted from the ETACS-ECU to the PHEV-ECU via CAN bus line.
  • As for the brake switch, the PHEV-ECU connector terminal BRSW 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 PHEV-ECU connector terminal BRSW changes. According to this change, the PHEV-ECU judges the state of the brake switch.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITIONS
Check Condition
  • The cruise control display screen is displayed.
Judgment Criteria
  • Open/short in stoplight switch circuit.
  • Open circuit in the brake switch circuit (between PHEV-ECU connector terminal BRSW and ground).
  • Malfunction of CAN bus line.
 
 
PROBABLE CAUSES
  • Malfunction of CAN bus system.
  • Damaged harness or connector.
  • Malfunction of the stoplight switch.
  • Malfunction of the ETACS-ECU.
  • Malfunction of the PHEV-ECU.
 
 
DIAGNOSIS
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Before replacing the ECU, ensure that the CAN bus lines is normal.
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn on the power supply mode of the electric motor switch.
(3) Diagnose the CAN bus line. [Refer to GROUP 54C - Explanation About The Scan Tool (M.U.T.-IIISE) CAN Bus Diagnostics ]
(4) Turn off the power supply mode of the electric motor switch.
Is the check result satisfactory?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Diagnosis, CAN Bus Diagnostic Table ).
 
STEP 2. Using scan tool (M.U.T.-IIISE), check the PHEV system data list.
Using scan tool (M.U.T.-IIISE), check the PHEV system data list (Refer to GROUP 54Da - Data List Reference Table ).
  • Item No.398: Stop light SW for speed control
Is the check result normal?
Go to Step 6.
Go to Step 3.
 
STEP 3. Check the stoplight operation.
Check the stoplight operation.
OK:
  • Brake pedal depressed: Stoplight will illuminate
  • Brake pedal not depressed: Stoplight does not illuminate
Is the check result normal?
Go to Step 4.
Check the stoplight system (Refer to GROUP 54A - Rear Combination Light, Symptom Procedures, Inspection Procedure 2: The stoplights do not illuminate or go out normally <Rear combination light BULB type>, or Inspection Procedure 3: The stoplights do not illuminate or go out normally <Rear combination light LED type>).
 
STEP 4. Using scan tool (M.U.T.-IIISE), check the ETACS data list.
Using scan tool (M.U.T.-IIISE), check the ETACS data list (Refer to GROUP 54A - ETACS, Diagnosis, Data List Reference Table ).
  • Item 290: Stoplight switch
Is the check result normal?
Go to Step 5.
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS, ETACS-ECU ).
 
STEP 5. Using scan tool (M.U.T.-IIISE), check the PHEV system data list.
Using scan tool (M.U.T.-IIISE), check the PHEV system data list (Refer to GROUP 54Da - Data List Reference Table ).
  • Item No.398: Stop light SW for speed control
Is the check result normal?
Go to Step 6.
Replace the PHEV-ECU (Refer to GROUP 54Da - PHEV-ECU ).
 
STEP 6. Using scan tool (M.U.T.-IIISE), check the PHEV system data list.
Using scan tool (M.U.T.-IIISE), check the PHEV system data list (Refer to GROUP 54Da - Data List Reference Table ).
  • Item No.397: Brake switch for speed control
Is the check result normal?
Go to Step 10.
Go to Step 7.
 
STEP 7. Check of open circuit, short circuit, and damage in BRSW line between PHEV-ECU connector and stoplight switch connector, and between stoplight switch connector and ground.
Is the check result normal?
Go to Step 8.
Repair the connector(s) or wiring harness.
 
STEP 8. Check the stoplight switch.
Refer to GROUP 35A - Brake Pedal, Inspection .
Is the check result normal?
Go to Step 9.
Replace the stoplight switch (Refer to GROUP 35A - Brake Pedal ).
 
STEP 9. Using scan tool (M.U.T.-IIISE), check the PHEV system data list.
Using scan tool (M.U.T.-IIISE), check the PHEV system data list (Refer to GROUP 54Da - Data List Reference Table ).
  • Item No.397: Brake switch for speed control
Is the check result normal?
Go to Step 10.
Replace the PHEV-ECU (Refer to GROUP 54Da - PHEV-ECU ).
 
STEP 10. Using scan tool (M.U.T.-IIISE), read the DTC.
(1) Use the scan tool (M.U.T.-IIISE), erase the DTC of the cruise control system.
(2) Turn ON the power supply mode of the electric motor switch, and press the cruise control ON/OFF switch to turn the cruise control system to ON (the cruise control display screen is turned on).
(3) With the cruise control switches not operated, depress the brake pedal for several seconds, and then read the DTC of the cruise control system (Refer to ).
Is DTC P0504 set?
Replace the PHEV-ECU (Refer to GROUP 54Da - PHEV-ECU ).
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 ).