Inspection Procedure 7

Inspection Procedure 7: Engine Does Not Start With Emergency Key (Cranking But No Initial Combustion).

TECHNICAL DESCRIPTION (COMMENT)
If the fuel injection does not work, KOS-ECU and the MFI system may have a problem. This symptom is not considered abnormal when the engine is started by an keyless operation key that has not been registered.

TROUBLESHOOTING HINTS
- Malfunction of the MFI system
- Malfunction of KOS-ECU
- Malfunction of CAN bus line
- Malfunction of the transponder
- VIN not programmed

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

STEP 1. Check the battery voltage.

Measure the battery voltage when cranking.
- The voltage should measure 8 volt or more.

Q: Is the measured voltage 8 volt or more?

YES : Go to Step 2.

NO : Check the battery (Refer to - Battery test). Battery Test

STEP 2. Using scan tool MB991958, diagnose the CAN bus line.







CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)." How to Connect the Scan Tool (M.U.T.-III)
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES : Go to Step 3.

NO : Repair the CAN bus line.

STEP 3. Using scan tool MB991958, read the MFI system diagnostic trouble code.

Check if DTC is set to the engine control module.

Q: Is the DTC set?

YES : Troubleshoot the MFI system (Refer to Diagnosis). Diagnostic Trouble Code Descriptions

NO : Go to Step 4.

STEP 4. Using scan tool MB991958, read the KOS-ECU diagnostic trouble code.

Check if DTC is set to the KOS.

Q: Is the DTC set?

YES : Refer to Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions

NO : Go to Step 5.

STEP 5. Check that the engine starts.

Q: Does the engine start?

YES : The procedure is complete.

NO : Refer to Diagnosis. Diagnostic Trouble Code Descriptions When the cause of the failure cannot be tracked down by the troubleshooting, replace KOS-ECU and register the ID codes.