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DTC B1134: ECU power supply
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
TECHNICAL DESCRIPTION (COMMENT)
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 orange.
 
 
DTC SET CONDITION
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 +B is detected to be "OFF".
    2. "ACC-ON" signal is received from the ETACS-ECU when IOD is "OFF" and +B is "ON"
 
 
TROUBLESHOOTING HINTS
  • 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
noteIf the fuse No.F13 (7.5 A) is blown, there may be a short to ground between the fuse and KOS&OSS-ECU. However, because the fuse No.F13 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 DTC set?
Go to Step 2.
Repair the connector(s) or wiring harness.
 
STEP 2. Using scan tool (M.U.T.-III), check data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the power supply mode of the engine switch to the "OFF" position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III) [Refer to "How to connect the Scan Tool (M.U.T.-III) "].
(2) Turn the power supply mode of the engine switch to "OFF".
(3) Check the KOS&OSS-ECU data list.
 
Item No.Check itemNormal 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
Are the check result normal?
(Normal conditions are displayed for all the items) : Go to Step 5.
(Normal condition is not displayed for item No. 28) : Go to Step 3.
(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.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 4. Check of open circuit in +B line between KOS&OSS-ECU connector and fusible link.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. Recheck for diagnostic trouble code.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from "OFF" to "ON".
(3) Check if DTC is set.
(4) Turn the power supply mode of the engine switch from "ON" to "OFF".
Is the DTC set?
Replace the KOS&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 ).