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DTC B1136: Stop light switch
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
When an open circuit or short to ground is detected in the stop light switch circuit system, or when the actual stop light switch status is different from the stop light switch status received from the ETACS-ECU via CAN, the OSS-ECU stores DTC B1136, and displays the power supply system error warning on 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:
    The time when the OSS-ECU obtained the stop light switch status deviates 1.5 seconds from the time when the ETACS-ECU obtained it.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of CAN bus line
  • Damaged wiring harness or connector (STP line, STP1 line)
  • ETACS-ECU malfunction
  • Malfunction of OSS-ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the power supply mode of the electric motor switch to the OFF before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect scan tool (M.U.T.-IIISE) ."
(2) Turn the power supply mode of the electric motor switch to ON.
(3) Diagnose the CAN bus line.
(4) Turn the power supply mode of the electric motor 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 power supply, short of ground and open circuit in STP1 line between stop light switch connector and OSS-ECU connector
noteBefore the wiring harness check, check the intermediate connector, and repair if necessary.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Check of short to power supply, short of ground and open circuit in STP 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.-IIISE), check other system data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the power supply mode of the electric motor switch to the OFF before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect scan tool (M.U.T.-IIISE) ."
(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.290: Stop light switch (Refer to GROUP 54A, ETACS - Service Data Reference Table .)
(4) Turn the power supply mode of the electric motor 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.-IIISE), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the power supply mode of the electric motor switch to the OFF 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 the power supply mode of the electric motor switch to OFF.
(3) Check the OSS-ECU data list.
  • Operate the brake pedal.
 
Operation stateItem No.Check itemDisplay
Brake pedal is depressed3Stoplight switchON
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 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 electric motor switch from OFF to ON.
(3) Check if DTC is set.
(4) Turn the power supply mode of the electric motor switch from ON to OFF.
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 ).