Code No.B1136 Stop lamp switch

caution

When replacing the ECU, always check that the communication circuit is normal.

DIAGNOSTIC FUNCTION

When an open circuit or short to earth is detected in the stop lamp switch circuit system, or when the actual stop lamp switch status is different from the stop lamp switch status received from the ETACS-ECU via CAN, the OSS-ECU sets diagnosis code No.B1136, and displays the power supply system error warning on the multi information display of the combination meter.

JUDGEMENT CRITERIA

Check Conditions

After OSS-ECU activation

Judgment Criterion

When the following conditions are met:
The time when the OSS-ECU obtained the stop lamp switch status deviates 1.5 seconds from the time when the ETACS-ECU obtained it.

PROBABLE CAUSES

Malfunction of CAN bus line
Damaged wiring harness or connector (STP line, STP1 line)
ETACS-ECU malfunction
Malfunction of OSS-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics

Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 2

Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting

). On completion, go to Step 2.

STEP 2. Check of short to power supply, short of earth and open circuit in STP1 line between stop lamp switch connector and OSS-ECU connector

note

Before the wiring harness check, check the intermediate connector, and repair if necessary.

Q. 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 earth and open circuit in STP line between stop lamp switch connector and ETACS-ECU connector

Q. Is the check result normal?

Go to Step 4

Repair the connector(s) or wiring harness.

STEP 4. M.U.T.-III other system data list

Check the ETACS-ECU data list.

Item No.290: Stop lamp switch (Refer to GROUP 54A - ETACS, Service Data Reference Table .)

Q. 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. M.U.T.-III data list

Check the OSS-ECU data list.

Operate the brake pedal.

Operation state	Item No.	Check item	Display
Brake pedal is depressed	3	Stop lamp switch	ON
Brake pedal released	3	Stop lamp switch	OFF

OK: Operation state and data list display agree with each other.

Q. Is the check result normal?

Go to Step 6

Replace the OSS-ECU and register the chassis number (Refer to

STEP 6. Check whether the diagnosis code is reset.

Q. Is the diagnosis code set?

Replace the OSS-ECU and register the chassis number (Refer to

Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction