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DTC B1131 Starter setting circuit fail
 
 
caution
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
When a short circuit of starter setting circuit system is detected, KOS&OSS-ECU sets DTC B1131. 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 amber.
 
 
JUDGMENT CRITERIA
Check Conditions
  • After KOS&OSS-ECU activation
Judgment Criterion
  • Starter setting circuit system is detected
 
 
PROBABLE CAUSES
  • Damaged wiring harness or connector (short to ground or short to power supply in STO line)
  • Malfunction of KOS&OSS-ECU
  • Malfunction of ECM
  • Malfunction of ETACS-ECU
 
 
DIAGNOSIS
STEP 1. Check of short to power supply, short to ground or open circuit in STO line between KOS&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 to power supply, short to ground or open circuit in ST 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 (ST terminal)
(1) Disconnect the ECM connector, and measure at the wiring harness side.
(2) Using the scan tool (M.U.T.-IIISE), set the forced power supply output to other than "IG START" (Refer to ).
(3) Measure the voltage between the ECM connector (ST terminal) and body ground.
OK: 1 volt or less
(4) Using the scan tool (M.U.T.-IIISE), set the forced power supply output to "IG START" (Refer to ).
(5) Measure the voltage between the ECM connector (ST terminal) and body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 4.
:
  • Go to Step 5.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check the data list
Check the KOS&OSS-ECU data list.
(1) Disconnect the ECM connector.
(2) Using the scan tool (M.U.T.-IIISE), perform the forced power supply output.
 
State of forced power supply outputItem No.Check itemDisplay
IG START8OSS power supply statusIG START
IG ONON
IG OFFOFF
OK: Depending on the state of forced power supply output, the display is turned START/ON/OFF.
Is the check result normal?
Replace the ECM and register the chassis number and key codes [Refer to GROUP 00 - How to Perform VIN Writing ].
Replace the KOS&OSS-ECU and register the ID codes (Refer to ).
 
STEP 5. Voltage measurement at ETACS-ECU connector (ST1 terminal)
(1) Measure the ETACS-ECU connector side by backprobing.
(2) Using the scan tool (M.U.T.-IIISE), set the forced power supply output to other than "IG START" (Refer to ).
(3) Measure the voltage between the ETACS-ECU connector (ST1 terminal) and body ground.
OK: 1 volt or less
(4) Using the scan tool (M.U.T.-IIISE), set the forced power supply output to "IG START" (Refer to ).
(5) Measure the voltage between the ETACS-ECU connector (ST1 terminal) and body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 6.
Replace the KOS&OSS-ECU and register the ID codes (Refer to ).
 
STEP 6. Check whether the DTC is set again.
Is the DTC set?
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS - ETACS-ECU ).
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).