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DTC B1136: Stop light switch
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
TECHNICAL DESCRIPTION (COMMENT)
When the stop light switch status is different from the brake switch information received from ETACS-ECU via CAN, KOS&OSS-ECU sets DTC B1136, and displays the power supply system error warning the combination meter, and flashes the indicator of engine switch in orange.
 
 
DTC SET CONDITION
Check Conditions
  • After KOS&OSS-ECU activation
Judgment Criterion
  • The difference between the stop light switch condition and the stop light switch information has been detected.
  • The stop light switch information from the ETACS-ECU cannot be received via CAN communication.
 
 
TROUBLESHOOTING HINTS
  • CAN bus line malfunction
  • Damaged wiring harness or connector (short to ground or open circuit between stop light switch and KOS&OSS-ECU or between stop light switch and ETACS-ECU)
  • ETACS-ECU malfunction
  • Malfunction of KOS&OSS-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the "OFF" position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III) [Refer to "How to connect scan tool (M.U.T.-III) "].
(2) Turn the power supply mode of the engine switch to "ON".
(3) Diagnose the CAN bus line.
(4) Turn the power supply mode of the engine switch to "OFF".
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Check of short to ground and open circuit in STP1 line between stop light switch connector and KOS&OSS-ECU connector
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Check of short to ground and open circuit in BKLP line between stop light switch connector and ETACS-ECU connector
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Using scan tool (M.U.T.-III), check other system data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III) [Refer to "How to connect scan tool (M.U.T.-III) "].
(2) After performing the forced power supply output (refer to forced power supply output procedure ) "IG-ON".
(3) Check the ETACS-ECU data list.
  • Item No.108: Stop light switch (Refer to GROUP 54A, ETACS, Service Data Reference Table ).
(4) Turn the power supply mode of the engine switch to "OFF".
Is the check result normal?
Go to Step 5.
Diagnose the ETACS-ECU (Refer to GROUP 54A, ETACS, Trouble Symptom Chart for Input Signal ).
 
STEP 5. Using scan tool (M.U.T.-III), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the "OFF" position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III) [Refer to "How to connect the Scan Tool (M.U.T.-III) "].
(2) Turn the power supply mode of the engine switch to "OFF".
(3) Check the KOS&OSS-ECU data list.
  • Operate the brake pedal.
 
Item No.Check itemOperation stateDisplay
22Stop light switchBrake pedal is depressedON
Brake pedal releasedOFF
OK: Operation state and data list display agree with each other.
Is the check result normal?
Go to Step 6.
Replace the KOS&OSS-ECU and register the VIN (Refer to ).
 
STEP 6. Recheck for diagnostic trouble code.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from "OFF" to "ON".
(3) Check if DTC is set.
(4) Turn the power supply mode of the engine switch from "ON" to "OFF".
Is the DTC set?
Replace the KOS&OSS-ECU and register the VIN (Refer to ).
Intermittent malfunction is suspected (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).