Use caution that
the cooling fan becomes activated when the forced power supply output of M.U.T.-III is performed
while the engine-ECU 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 earth) of starter setting circuit
system is detected, OSS-ECU sets the diagnosis code No.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.
JUDGEMENT CRITERIA
Check Conditions
After OSS-ECU activation
Judgment Criterion
When the following conditions are met:
When the starter setting signal is ON, the starter
setting circuit voltage is less than 1.5 V.
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 earth or
short to power supply in ST line, STO line or STOE line)
Malfunction of OSS-ECU
ETACS-ECU malfunction
Malfunction of engine-ECU
DIAGNOSIS PROCEDURE
STEP 1. Check of short to power supply, short to earth, and
open circuit in ST, STO line between OSS-ECU connector and ETACS-ECU connector
note
Before the wiring harness check, check the joint connector, and repair if necessary.
Q.
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 earth, and open circuit
in STOE line between ETACS-ECU connector and engine-ECU connector
Q.
Is the check result normal?
Go to Step 3
NO : Repair the connector(s) or wiring harness.
STEP 3. Voltage measurement at engine-ECU connector (STOE terminal)
(1)Disconnect the engine-ECU connector, and measure at the wiring harness side.
(2)Using the M.U.T.-III, set the forced power supply output to other than "IG-ST".(Refer
to .)
(3)Measure the voltage between the engine-ECU connector (STOE terminal) and body earth. OK: 1 V or less
(4)Using the M.U.T.-III, set the forced power supply output to "IG-ST".(Refer to .)
(5)Measure the voltage between the engine-ECU connector (STOE terminal) and body earth. OK: System voltage
Q.
Is the check result normal?
Go to Step 4
NO :
STEP 4. M.U.T.-III data list
Check the OSS-ECU data list.
(1)Disconnect the engine-ECU connector.
(2)Using the M.U.T.-III, perform the forced power supply output.
State of forced power supply output
Item No.
Check item
Display
IG-ST
13
Cranking signal output(monitor)
ON
Other than IG-ST
OFF
OK: Depending on the state of forced power supply output, the display is turned
ON/OFF.
Q.
Is the check result normal?
Replace the engine-ECU and register the chassis number and key codes [Refer
to GROUP 00 - How to Perform Chassis Number (Chassis No.) Writing ].
Replace the OSS-ECU and register the chassis number (Refer to ).
STEP 5. Voltage measurement at ETACS-ECU connector (STOE terminal)
(1)Measure the ETACS-ECU connector side by backprobing.
(2)Using the 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 (STOE terminal) and body earth. OK: 1 V or less
(4)Using the M.U.T.-III, set the forced power supply output to "IG-ST".(Refer to .)
(5)Measure the voltage between the ETACS-ECU connector (STOE terminal) and body earth. OK: System voltage
Q.
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. Check whether the diagnosis code is reset.
Q.
Is the diagnosis code 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 ).
Go to Step 2
Repair the connector(s) or wiring harness.
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