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DTC B1131: START setting circuit
 
 
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 screen to the multi information display of the combination meter, and flashes the indicator of engine switch in amber.
 
 
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.
 
 
PROBABLE CAUSES
  • Damaged wiring harness or connector (short to ground or short to power supply in ST line, STO line or ST2 line)
  • Malfunction of OSS-ECU
  • ETACS-ECU malfunction
  • Malfunction of engine control module
 
 
DIAGNOSIS
STEP 1. Check of short to power supply, short to ground, and open circuit in ST, STO line between OSS-ECU connector and ETACS-ECU connector
noteBefore the wiring harness check, check the joint connector, and repair if necessary.
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, and open circuit in ST2 line between ETACS-ECU connector and engine control module connector
Is the check result normal?
Go to Step 3.
: Repair the connector(s) or wiring harness.
 
STEP 3. Voltage measurement at engine control module connector (ST2 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 (ST2 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 (ST2 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.-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.
 
State of forced power supply outputItem No.Check itemDisplay
IG-ST13Cranking /ST SIG. output (monitor)ON
Other than IG-STOFF
State of forced power supply outputItem No.Check itemDisplay
IG-ST13Cranking /ST SIG. 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 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 5. Voltage measurement at ETACS-ECU connector (ST2 terminal)
(1) Measure the ETACS-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 ETACS-ECU connector (ST2 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 ETACS-ECU connector (ST2 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 OSS-ECU and register the chassis number (Refer to ). Then go to Step 6.
 
STEP 6. 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 ETACS-ECU.
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).