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DTC B1136 Stop light switch
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
When the stop light switch status is different from the brake switch information received from ETACS-ECU via CAN, OSS-ECU sets the DTC B1136, and displays the power supply system error warning screen to the multi information display of the combination meter.
 
 
DTC SET CONDITION
Check Conditions
  • After OSS-ECU activation
Judgment Criterion
  • When the following conditions are met:
    1. When the stop light switch is OFF and the brake switch status is ON, 1.5 seconds or more have elapsed
    2. When the stop light switch is ON and the brake switch status is OFF, 1.5 seconds or more have elapsed
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness or connector (short to ground or open circuit between stop light switch and OSS-ECU or between stop light switch and ETACS-ECU)
  • ETACS-ECU malfunction
  • Malfunction of OSS-ECU
 
 
DIAGNOSIS
STEP 1. Check of short to ground and open circuit in signal line between stop light switch connector and OSS-ECU connector
Is the check result normal?
Go to Step 2.
Repair the connector(s) or wiring harness.
 
STEP 2. Check of short to ground and open circuit in signal line between stop light switch connector and ETACS-ECU connector
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Using scan tool MB991958, check other system data list.
Check the ETACS-ECU data list.
  • Item No.290: Stop light switch (Refer to GROUP 54A - ETACS, Service Data Reference Table .)
Is the check result normal?
Go to Step 4.
Diagnose the ETACS-ECU. (Refer to GROUP 54A - ETACS, Trouble Symptom Chart for Input Signal .)
 
STEP 4. Using scan tool MB991958, check data list.
Check the OSS-ECU data list.
  • Operate the brake pedal.
 
Operation stateItem No.Check itemDisplay
Brake pedal is depressed3Stop light switchON
Brake pedal releasedOFF
OK: Operation state and data list display agree with each other.
Is the check result normal?
Go to Step 5.
Replace the OSS-ECU and register the VIN (Refer to ).
 
STEP 5. Check whether the DTC is reset.
Is the DTC set?
Replace the 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 ).