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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 MB991958 is performed while the ECM 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 sets the DTC B1131. 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:
    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 STOE line)
  • Malfunction of OSS-ECU
  • ETACS-ECU malfunction
  • Malfunction of ECM
 
 
DIAGNOSIS
STEP 1. Check of short circuit in STO line between OSS-ECU connector and ETACS-ECU connector
Is the check result normal?
Go to Step 2
Repair the connector(s) or wiring harness.
 
STEP 2. Check of short circuit in STOE line between ETACS-ECU connector and ECM connector
Is the check result normal?
Go to Step 3
Repair the connector(s) or wiring harness.
 
STEP 3. Voltage measurement at ECM connector (STOE terminal)
(1) Disconnect the ECM connector, and measure at the wiring harness side.
(2) Using the scan tool MB991958, set the forced power supply output to other than "IG-ST" (Refer to forced power supply output procedure ).
(3) Measure the voltage between the ECM connector (STOE terminal) and body ground.
OK: 1 V or less
(4) Using the scan tool MB991958, set the forced power supply output to "IG-ST" (Refer to forced power supply output procedure ).
(5) Measure the voltage between the ECM connector (STOE terminal) and body ground.
OK: Battery voltage
Is the check result normal?
Go to Step 4
  • Go to Step 5
 
STEP 4. Using scan tool MB991958, check data list.
Check the OSS-ECU data list.
(1) Disconnect the ECM connector.
(2) Using the scan tool MB991958, perform the forced power supply output.
 
State of forced power supply outputItem No.Check itemDisplay
IG-ST13Cranking signal output(monitor)ON
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 ECM 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 5. Voltage measurement at ETACS-ECU connector (STOE terminal)
(1) Measure the ETACS-ECU connector side by backprobing.
(2) Using the scan tool MB991958, set the forced power supply output to other than "IG-ST" (Refer to forced power supply output procedure ).
(3) Measure the voltage between the ETACS-ECU connector (STOE terminal) and body ground.
OK: 1 V or less
(4) Using the scan tool MB991958, set the forced power supply output to "IG-ST" (Refer to forced power supply output procedure ).
(5) Measure the voltage between the ETACS-ECU connector (STOE terminal) and body ground.
OK: Battery voltage
Is the check result normal?
Go to Step 6
Replace the OSS-ECU and register the VIN (Refer to ). Then go to Step 6
 
STEP 6. Check whether the DTC is reset.
Is the DTC set?
Replace the ETACS-ECU.
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).