Inspection Procedure
5: Engine does not start (cranking is not performed).
caution
Before replacing the ECU,
ensure that the power supply circuit, the earth circuit and the communication circuit are normal.
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 OSS-ECU malfunction may be
present.
PROBABLE CAUSES
Malfunction of battery
Damaged wiring harness or connector (open circuit in STOE line)
Error in engine starting circuit system
Stop lamp switch malfunction
Malfunction of the CAN bus line
Malfunction of OSS-ECU
Malfunction of AS&G-ECU
Engine-ECU malfunction
ETACS-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. M.U.T.-III diagnosis code
Check if the diagnosis code is set to OSS-ECU.
Q.
Is the diagnosis code set?
YES : Diagnose the OSS-ECU. Refer to .
Go to Step 3
STEP 3. M.U.T.-III data list
Check the OSS-ECU data list.
Operate the brake pedal.
Operation state
Item No.
Check item
Display
Brake pedal is depressed
3
Stop lamp switch
ON
Brake pedal released
OFF
OK: Operation state and data list display agree with each other.
Q.
Is the check result normal?
Go to Step 5
NO : Go to Step 4
STEP 4. Stop Lamp Switch Check
Continuity check of stop lamp switch (Refer to GROUP 35A - Brake Pedal ).
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 ).
Replace the stop lamp switch.
STEP 5. Voltage measurement at ETACS-ECU connector (STOE terminal)
(1)With the ETACS-ECU connector kept connected, measure 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?
YES : Go to Step 6
NO : Replace the OSS-ECU and register the chassis number (Refer to ).
STEP 6. M.U.T.-III other system data list
Check the engine-ECU data list.
(1)Using the M.U.T.-III, set the forced power supply output to "IG-ST".(Refer to .)
(2)Check the engine-ECU data list.
Item No.
Check item
Display
79
Cranking signal (Ignition switch-ST)
ON
OK: Operation state and data list display agree with each other.
(3)Using the M.U.T.-III, set the forced power supply output to other than "IG-ST".(Refer
to .)
(4)Check the engine-ECU data list.
Item No.
Check item
Display
79
Cranking signal (Ignition switch-ST)
OFF
OK: Operation state and data list display agree with each other.
Q.
Is the check result normal?
Go to Step 8
Go to Step 7
STEP 7. Check of open circuit in STOE line between ETACS-ECU connector
and engine-ECU connector
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 ].
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 13A - Troubleshooting .)
Go to Step 2
Replace the battery.
: Go to Step 4