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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 OSS power supply, OSS-ECU sets the DTC 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.
 
 
DTC SET CONDITION
Check Conditions
  • After OSS-ECU activation
Judgment Criterion
  • When the following conditions are met, and 1 second or more has elapsed.
    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.
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness or connector (open circuit in +B line)
  • Malfunction of OSS-ECU
  • ETACS-ECU malfunction
noteIf the IGN fuse (10 A) is blown, there may be a short to ground 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
STEP 1. Using scan tool MB991958, check data list.
Check the OSS-ECU data list.
 
Item No.Check itemNormal condition
18+B1 Power supply voltage (AD)Battery voltage
19+B2 Power supply voltage (AD)Battery voltage
OK: Normal values are displayed for all the items
Are 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 open circuit in +B1 line between OSS-ECU connector and battery
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 3. Check of open circuit in +B2 line between OSS-ECU connector and battery
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Check whether the DTC is reset.
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 ).