Code No.B1134 ECU power supply

caution

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

DIAGNOSTIC FUNCTION

When an open circuit is detected in one of the two systems of power supply, KOS&OSS-ECU sets diagnosis code No.B1134. At the same time, KOS&OSS-ECU displays the power supply system error warning to the combination meter, and flashes the indicator of engine switch in orange.

JUDGEMENT CRITERIA

Check Conditions

After KOS&OSS-ECU activation

Judgement Criterion

When the following conditions are met, and 1 second or more has elapsed.

IOD is detected to be "ON" and +B is detected to be "OFF".
ACC-ON signal is received from the ETACS-ECU when IOD is "OFF" and +B is "ON"

PROBABLE CAUSES

Malfunction of ETACS-ECU battery power supply system
Damaged wiring harness or connector (open circuit in +B line)
Blown out fuse
Malfunction of KOS&OSS-ECU

note

If the fuse No.F13 (7.5 A) is blown, there may be a short to earth between the fuse and KOS&OSS-ECU or between the fuse and electric steering lock power supply. However, because the fuse No.F13 is branched off, determine the root cause while referring to the Electrical Wiring Manual.

DIAGNOSIS PROCEDURE

STEP 1. Check the battery power supply circuit to the ETACS-ECU.

Refer to GROUP 54A - ETACS - Inspection Procedure 1 Check the battery power supply circuit to the ETACS-ECU

Q. Is the diagnosis code set?

Go to Step 2.

Repair the connector(s) or wiring harness.

STEP 2. M.U.T.-III data list

Check the KOS&OSS-ECU data list.

Item No.	Check item	Normal condition
28	+B1 Power supply voltage (AD)	System voltage
29	+B2 Power supply voltage (AD)	System voltage

OK: Normal values are displayed for all the items

Q. Are the check result normal?

YES (Normal conditions are displayed for all the items)

: Go to Step 5.

NO (Normal condition is not displayed for item No. 28)

: Go to Step 3.

NO (Normal condition is not displayed for item No. 29)

: Go to Step 4.

STEP 3. Check of open circuit in IOD line between KOS&OSS-ECU connector and fusible link

Q. Is the check result normal?

Go to Step 5.

Repair the connector(s), wiring harness or fuse.

STEP 4. Check of open circuit in +B line between KOS&OSS-ECU connector and fusible link

Q. Is the check result normal?

Go to Step 5.

Repair the connector(s), wiring harness or fuse.

STEP 5. Check whether the diagnosis code is set again.

Q. Is the diagnosis code set?

Replace the KOS&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