Inspection Procedure 14: Ignition Timing Deviation

COMMENTS ON TROUBLE SYMPTOM

The failure could possibly be caused by the failed crank angle sensor, faulty camshaft position sensor, improper assembled timing belt and so on.

PROBABLE CAUSES

Failed crank angle sensor
Failed camshaft position sensor
Timing belt in out of place
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is diagnosis code set?

	Inspection chart for diagnosis code (Refer to ).

	Go to Step 2.

STEP 2. Perform output wave pattern measurement at crank angle sensor and camshaft position sensor (Using an oscilloscope).

<Crank angle sensor>

Use the test harness (MB991709) to connect crank angle sensor connector, and measure at the pick-up harness.
Engine: Idling
Transmission: Neutral
Voltage between terminal engine-ECU SGT line and earth.

<Camshaft position sensor>

Use the test harness (MB991709) to connect camshaft position sensor connector, and measure at pick-up harness.
Engine: Idling
Transmission: Neutral
Voltage between terminal engine-ECU SGC line and earth.

OK: The timings on the output wave pattern at the both sensors should be the same as the specification in the inspection procedure using an oscilloscope (Refer to ).

Q. Is the check result normal?

	Go to Step 3.

	Go to Step 4.

STEP 3. Check the trouble symptom.

Q. Does the trouble symptom persist?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 4. Check crank angle sensor and camshaft position sensor for correct mounting condition.

Q. Is the check result normal?

	Go to Step 5.

	Repair.

STEP 5. Check timing mark on the timing belt.

Q. Is the check result normal?

	Go to Step 6.

	Align the timing marks.

STEP 6. Check the crank shaft sensing blade.

Q. Is the check result normal?

	Go to Step 7.

	Replace crank shaft sensing blade.

STEP 7. Check the camshaft position sensing cylinder.

Q. Is the check result normal?

	Go to Step 8.

	Replace camshaft position sensing cylinder.

STEP 8. Replace the crank angle sensor.

After replacing the crank angle sensor, re-check the trouble symptoms.

Q. Does trouble symptom persist?

	Go to Step 9.

	Check end.

STEP 9. Replace the camshaft position sensor.

After replacing the camshaft position sensor, re-check the trouble symptoms.

Q. Does trouble symptom persist?

	Replace engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).