Inspection Procedure 5
Inspection Procedure 5: Engine does not start (cranking is not performed).
CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
TECHNICAL DESCRIPTION (COMMENT)
When the engine does not start (cranking is not performed), the battery malfunction, stop light switch malfunction [CVT vehicle], clutch switch malfunction [M/T vehicle], engine starting circuit malfunction, or OSS-ECU malfunction may be present.
TROUBLESHOOTING HINTS
- Malfunction of battery
- Damaged wiring harness or connector (open circuit in STOE line)
- Error in engine starting circuit system
- Stop light switch malfunction[ CVT vehicle]
- Clutch switch malfunction[ M/T vehicle]
- Malfunction of the CAN bus line
- Malfunction of OSS-ECU
- Malfunction of AS&G-ECU
- ECM malfunction
- ETACS-ECU malfunction
DIAGNOSIS
STEP 1. Battery check
Perform the battery test to check the battery status Battery Test).
Q. Is the check result normal?
YES Go to Step 2.
NO Replace the battery.
STEP 2. M.U.T.-III diagnostic trouble code
(1)
CAUTION:
To prevent damage to scan tool (MB991958), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (MB991958).
Connect scan tool MB991958. Refer to "How to connect scan tool (M.U.T.-III) Reading and Clearing Diagnostic Trouble Codes."
(2)After performing the forced power supply output (refer to forced power supply output procedure Programming and Relearning) "IG-ON".
(3)Check if the DTC is set to OSS-ECU.
(4)Turn the power supply mode of the engine switch to OFF.
Q. Is the DTC set?
YES : Diagnose the OSS-ECU. Refer to diagnostic trouble code chart Keyless Operation System (KOS).
NO [CVT vehicle] : Go to Step 3.
NO [M/T vehicle] : Go to Step 5.
STEP 3. Using scan tool MB991958, check data list.
Check the OSS-ECU data list.
- Operate the brake pedal.
OK: Operation state and data list display agree with each other.
Q. Is the check result normal?
YES Go to Step 8.
NO : Go to Step 4.
STEP 4. Stop light switch check
(1)Remove the stop light switch Service and Repair).
(2)Check continuity when the stop light switch is operated to position Testing and Inspection).
Q. Is the check result normal?
YES Intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).
NO Replace the stop light switch.
STEP 5. Using scan tool MB991958, check data list.
Check the OSS-ECU data list.
- Operate the clutch pedal.
OK: Operation state and data list display agree with each other.
Q. Is the check result normal?
YES Go to Step 8.
NO : Go to Step 6.
STEP 6. Check of open circuit in CLMS line between OSS-ECU connector and clutch switch connector
Q. Is the check result normal?
YES Go to Step 7.
NO Repair the connector(s) or wiring harness.
STEP 7. Clutch switch check
Continuity check of clutch switch Testing and Inspection).
Q. Is the check result normal?
YES Intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).
NO Replace the clutch switch.
STEP 8. Voltage measurement at ETACS-ECU connector (STOE terminal)
(1)With the ETACS-ECU connector kept connected, measure by backprobing.
(2)Using the scan tool MB991958, set the forced power supply output to other than
"IG-ST" (Refer to forced power supply output procedure Programming and Relearning).
(3)Measure the voltage between the ETACS-ECU connector (STOE terminal) and body ground.
OK: 1 V or less
(4)Using the scan tool MB991958, set the forced power supply output to "IG-ST" (Refer to forced power supply output procedure Programming and Relearning).
(5)Measure the voltage between the ETACS-ECU connector (STOE terminal) and body ground.
OK: Battery voltage
Q. Is the check result normal?
YES Go to Step 9.
NO : Replace the OSS-ECU and register the VIN (Refer to Programming and Relearning).
STEP 9. Using scan tool MB991958, check other system data list.
Check the ECM data list.
(1)Using the scan tool MB991958, set the forced power supply output to "IG-ST" (Refer to forced power supply output procedure Programming and Relearning).
(2)Check the ECM data list.
OK: Operation state and data list display agree with each other.
(3)Using the scan tool MB991958, set the forced power supply output to other than
"IG-ST" (Refer to forced power supply output procedure Programming and Relearning).
(4)Check the ECM data list.
OK: Operation state and data list display agree with each other.
Q. Is the check result normal?
YES Go to Step 11.
NO Go to Step 10.
STEP 10. Check of open circuit in STOE line between ETACS-ECU connector and ECM connector
Q. Is the check result normal?
YES Replace the ECM and register the VIN and key codes Testing and Inspection).
NO Repair the connector(s) or wiring harness.
STEP 11. Check of the troubles
Check whether the engine is started (cranking is performed).
Q. Is the check result normal?
YES Intermittent malfunction is suspected How to Cope With Intermittent Malfunctions).
NO There is a problem with the engine starting circuit system of ECM. Carry out the troubleshooting relevant to the engine starting circuit system Symptom Chart).