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Inspection Procedure 5: Engine does not start (cranking is not performed).
 
 
cautionBefore 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, 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
  • 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 (Refer to GROUP 54A - Battery ).
Is the check result normal?
Go to Step 2.
Replace the battery.
 
STEP 2. M.U.T.-III diagnostic trouble code
(1)
cautionTo 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) ."
(2) After performing the forced power supply output (refer to forced power supply output procedure ) "IG-ON".
(3) Check if the DTC is set in OSS-ECU.
(4) Turn the power supply mode of the engine switch to OFF.
Is the DTC set?
Diagnose the OSS-ECU. Refer to diagnostic trouble code chart .
Go to Step 3.
 
STEP 3. Using scan tool MB991958, check data list.
Check the OSS-ECU data list.
  • Operate the brake pedal.
 
Operation stateItem No.Check itemDisplay
Brake pedal is depressed3Stop light switchON
Brake pedal releasedOFF
OK: Operation state and data list display agree with each other.
Is the check result normal?
Go to Step 5.
Go to Step 4.
 
STEP 4. Stop light switch check
(1) Remove the stop light switch (Refer to GROUP 35A - Brake Pedal ).
(2) Check continuity when the stop light switch is operated to position (Refer to GROUP 35A - Brake Pedal ).
 
Check conditionTerminal connector of testerNormal condition
At free position1 - 2 (for stoplight switch)Continuity exists (2 Ω or less)
3 - 4 (for cruise control)No continuity
Press the plunger from the edge of the outer case by the dimension shown in the figure.1 - 2 (for stoplight switch)No continuity
3 - 4 (for cruise control)Continuity exists (2 Ω or less)
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 light 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 scan tool MB991958, set the forced power supply output to other than "IG-ST" (Refer to forced power supply output procedure ).
(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 ).
(5) Measure the voltage between the ETACS-ECU connector (STOE terminal) and body ground.
OK: Battery voltage
Is the check result normal?
Go to Step 6.
Replace the OSS-ECU and register the VIN (Refer to ).
 
STEP 6. 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 ).
(2) Check the ECM data list.
 
Item No.Check itemDisplay
79Cranking signal
(Ignition switch-ST)
ON
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 ).
(4) Check the ECM data list.
 
Item No.Check itemDisplay
79Cranking signal
(Ignition switch-ST)
OFF
OK: Operation state and data list display agree with each other.
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 ECM connector
Is the check result normal?
Replace the ECM and register the VIN and key codes (Refer to GROUP 00 - How to Perform VIN Writing ).
Repair the connector(s) or wiring harness.
 
STEP 8. Check of the troubles
Check whether the engine is started (cranking is performed).
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 ECM. Carry out the troubleshooting relevant to the engine starting circuit system (Refer to GROUP 13A - Troubleshooting <2.0L ENGINE> or GROUP 13C - Troubleshooting <2.4L ENGINE>).