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 OSS power supply, OSS-ECU sets the diagnosis code No.B1134. At the same time, OSS-ECU displays the power supply system error warning screen to the multi information display of the combination meter, and flashes the indicator of engine switch in orange.

JUDGEMENT CRITERIA


Check Conditions
Judgment Criterion
  1. +B1 is detected to be ON and +B2 is detected to be OFF.
  2. When +B1 is OFF and +B2 is ON, OSS-ECU detects that the IOD fuse is mounted.

PROBABLE CAUSES



note If the IGN fuse (10 A) is blown, there may be a short to earth between the fuse and OSS-ECU or between the fuse and electric steering lock power supply. However, because the IGN fuse is branched off, determine the root cause while referring to the Electrical Wiring Manual.

DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III data list


Check the OSS-ECU data list.
Item No.
Check item
Normal condition
18
+B1 Power supply voltage (AD)
System voltage
19
+B2 Power supply voltage (AD)
System voltage
OK: Normal values are displayed for all the items

Q. Is the check result normal?

Normal conditions are displayed for all the items. : Go to Step 4.
Normal condition is not displayed for item No.18 : Go to Step 2.
Normal condition is not displayed for item No.19 : Go to Step 3.

STEP 2. Check of short to power supply, short to earth, and open circuit in +B1 line between OSS-ECU connector and fusible link


note Before the wiring harness check, check the joint connector, ETACS-ECU connector, and repair if necessary.

Q. Is the check result normal?

Go to Step 4.
Repair the connector(s) or wiring harness.

STEP 3. Check of short to power supply, short to earth, and open circuit in +B2 line between OSS-ECU connector and fusible link


note Before the wiring harness check, check the joint connector, ETACS-ECU connector, and repair if necessary.

Q. Is the check result normal?

Go to Step 4.
Repair the connector(s) or wiring harness.

STEP 4. 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 ).