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DTC B1134 ECU power supply
 
 
cautionWhen 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 DTC 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 amber.
 
 
JUDGMENT CRITERIA
Check Conditions
  • After KOS&OSS-ECU activation
Judgment Criterion
  • When the following conditions are met, and 1 second or more has elapsed.
    1. IOD is detected to be ON and +B1 is detected to be OFF.
    2. When +B1 is ON and IOD is OFF, KOS&OSS-ECU detects that the IOD FUSE is mounted.
 
 
PROBABLE CAUSES
  • Malfunction of ETACS-ECU battery power supply system
  • Damaged wiring harness or connector (open circuit in +B1 line)
  • Blown out fuse
  • Malfunction of KOS&OSS-ECU
noteIf the fuse No.10 (10 A) is blown, there may be a short to ground between the fuse and KOS&OSS-ECU power supply. However, because the fuse No.10 is branched off, determine the root cause while referring to the Electrical Wiring Manual.
 
 
DIAGNOSIS
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 .
Is the check result normal?
Go to Step 2.
Repair the connector(s) or wiring harness.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check the data list
Check the KOS&OSS-ECU data list.
 
Item No.Check itemNormal condition
9ECU power supply voltage (IOD)Battery positive voltage
10ECU power supply voltage (+B)Battery positive voltage
Item No.Check itemNormal condition
9ECU power supply voltage (IOD)Battery positive voltage
10ECU power supply voltage (+B)Battery positive voltage
OK: Normal values are displayed for all the items
Are the check result normal?
: Go to Step 5.
: Go to Step 3.
: Go to Step 4.
 
STEP 3. Check of open circuit in IOD line between KOS&OSS-ECU connector and fusible link
Is the check result normal?
Go to Step 5.
Repair the connector(s), wiring harness or fuse.
 
STEP 4. Check of open circuit in +B1 line between KOS&OSS-ECU connector and fusible link
Is the check result normal?
Go to Step 5.
Repair the connector(s), wiring harness or fuse.
 
STEP 5. Check whether the DTC is set again.
Is the DTC set?
Replace the KOS&OSS-ECU and register the ID codes (Refer to ).
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).