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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 stores 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 electric motor switch in amber.
 
 
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. However, because the IGN fuse is branched off, determine the root cause while referring to the Electrical Wiring Manual.
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the power supply mode of the electric motor switch to the OFF before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn the power supply mode of the electric motor switch to OFF.
(3) Check the OSS-ECU data list.
 
Item No.Check itemNormal 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
Are the check result normal?
: Go to Step 4.
: Go to Step 2.
: Go to Step 3.
 
STEP 2. Check of short to power supply, short to ground, and open circuit in +B1 line between OSS-ECU connector and fusible link
noteBefore the wiring harness check, check the joint connector, ETACS-ECU connector, and repair if necessary.
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 ground, and open circuit in +B2 line between OSS-ECU connector and fusible link
noteBefore the wiring harness check, check the joint connector, ETACS-ECU connector, and repair if necessary.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Recheck for diagnostic trouble code.
(1) Erase the DTC.
(2) Turn the power supply mode of the electric motor switch from OFF to ON.
(3) Check if DTC is set.
(4) Turn the power supply mode of the electric motor switch from ON to OFF.
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 ).