Inspection Procedure 16: Engine does not start (Cranking is not performed).
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Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
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COMMENTS ON TROUBLE SYMPTOM
When the engine does not start (cranking is not performed), the battery malfunction, stop lamp switch malfunction, engine starting circuit malfunction, or KOS&OSS-ECU malfunction may be present.
PROBABLE CAUSES
- Malfunction of battery
- Damaged wiring harness or connector (open circuit in ST line)
- Error in engine starting circuit system
- Stop lamp switch malfunction
- Malfunction of the CAN bus line
- Malfunction of KOS&OSS-ECU
- Engine-ECU malfunction
PROBABLE CAUSES
STEP 1. Battery check
Perform the battery test to check the battery status (Refer to GROUP 54A - Battery 
).
Q.
Is the check result normal?
Go to Step 2.
Replace the battery.
STEP 2. Check that the M.U.T.-III communicates with this system
Check that the communication with M.U.T.-III is possible.
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(1)Turn on and off any of the door switches several times, or open any of the doors.
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(2)Check that KOS&OSS-ECU can communicate with the M.U.T.-III.
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Q.
Is the check result normal?
Go to Step 3.
Perform troubleshooting for inspection procedure 3 "Abnormal in KOS&OSS-ECU power supply and earth circuits ".
STEP 3. M.U.T.-III diagnosis code
Check if the diagnosis code is set in the KOS&OSS-ECU.
Q.
Is the diagnosis code set?
YES : Diagnose the KOS&OSS-ECU. Refer to .
NO 
: Go to Step 4.
STEP 4. M.U.T.-III data list
Check the KOS&OSS-ECU data list.
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Item No.
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Check item
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Operation state
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Display
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22
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Stop lamp switch
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Brake pedal is depressed
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ON
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Brake pedal released
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OFF
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OK: Operation state and data list display agree with each other.
Q.
Is the check result normal?
YES : Go to Step 6.
NO : Go to Step 5.
STEP 5. Stop lamp switch check
Continuity check of stop lamp switch (Refer to GROUP 35A - Brake Pedal ).
Q.
Is the check result normal?
Go to Step 6.
Replace the stop lamp switch.
STEP 6. M.U.T.-III other system data list
Check the engine-ECU data list.
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(1)Using the M.U.T.-III, set the forced power supply output to "IG-ST". (Refer to .)
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(2)Check the engine-ECU data list.
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Item No.
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Check item
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Display
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79
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Cranking signal
(Ignition switch-ST)
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ON
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OK: Operation state and data list display agree with each other.
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(3)Using the M.U.T.-III, set the forced power supply output to other than "IG-ST". (Refer to .)
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(4)Check the engine-ECU data list.
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Item No.
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Check item
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Display
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79
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Cranking signal
(Ignition switch-ST)
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OFF
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OK: Operation state and data list display agree with each other.
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Q.
Is the check result normal?
Go to Step 8.
Go to Step 7.
STEP 7. Check of short to power supply, short to earth or open circuit in ST line between KOS&OSS-ECU connector and engine-ECU connector
Q.
Is the check result normal?
Replace the KOS&OSS-ECU and register the chassis number (Refer to ).
Repair the connector(s) or wiring harness.
STEP 8. Check of the troubles
Check whether the engine is started (cranking is performed).
Q.
Is the check result normal?
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
There is a problem with the engine starting circuit system of engine-ECU. Carry out the troubleshooting relevant to the engine starting circuit system. (Refer to GROUP 13B - Troubleshooting <6B3> or GROUP 13C - Troubleshooting <4N1>.)