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DTC B1131: Starter setting circuit fail
 
 
caution
  • Use caution that the cooling fan becomes activated when the forced power supply output of scan tool (M.U.T.-III) is performed while the engine control module connector is disconnected. (Fail-safe for ETACS-ECU)
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
When a short circuit (short to power supply, short to ground) of starter setting circuit system is detected, OSS-ECU stores DTC B1131. At the same time, 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 OSS-ECU activation
Judgment Criterion
  • When the following conditions are met:
    1. When the starter setting signal is ON, the starter setting circuit voltage is less than 1.5 V.
    2. When the starter setting signal is OFF, the circuit voltage is 3.5 V or more.
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness or connector (short to ground or short to power supply in STO line or ST line)
  • Malfunction of OSS-ECU
  • Malfunction of engine control module
 
 
DIAGNOSIS
STEP 1. Check of short or open circuit in ST line between OSS-ECU connector and engine control module connector
Is the check result normal?
Go to Step 2.
Repair the connector(s) or wiring harness.
 
STEP 2. Voltage measurement at engine control module connector (ST terminal)
(1) Disconnect the engine control module connector, and measure at the wiring harness side.
(2) Using the scan tool (M.U.T.-III), set the forced power supply output to other than "IG-ST" (Refer to ).
(3) Measure the voltage between the engine control module connector (ST terminal) and body ground.
OK: 1 V or less
(4) Using the scan tool (M.U.T.-III), set the forced power supply output to "IG-ST" (Refer to ).
(5) Measure the voltage between the engine control module connector (ST terminal) and body ground.
OK: System voltage
Is the check result normal?
Go to Step 3.
  • Go to Step 4.
 
STEP 3. Using scan tool (M.U.T.-III), check data list.
Check the OSS-ECU 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) Disconnect the engine control module connector.
(4) Using the scan tool (M.U.T.-III), perform the forced power supply output.
 
Item No.Check itemState of forced power supply outputDisplay
13Cranking signal output(monitor)IG-STON
Other than IG-STOFF
OK: Depending on the state of forced power supply output, the display is turned ON/OFF.
Is the check result normal?
Replace the engine control module and register the VIN and key codes (Refer to GROUP 00 - How to Perform VIN Writing ).
Replace the OSS-ECU and register the VIN (Refer to ).
 
STEP 4. Voltage measurement at OSS-ECU connector (ST terminal)
(1) Measure the OSS-ECU connector side by backprobing.
(2) Using the scan tool (M.U.T.-III), set the forced power supply output to other than "IG-ST" (Refer to ).
(3) Measure the voltage between the OSS-ECU connector (ST terminal) and body ground.
OK: 1 V or less
(4) Using the scan tool (M.U.T.-III), set the forced power supply output to "IG-ST" (Refer to ).
(5) Measure the voltage between the OSS-ECU connector (ST terminal) and body ground.
OK: System voltage
Is the check result normal?
Go to Step 5.
Replace the OSS-ECU and register the VIN (Refer to ).
 
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 stored.
(4) Turn the power supply mode of the engine switch from ON to OFF.
Is the DTC stored?
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 ).