Inspection Procedure 14: Ignition Timing Offset






COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



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 B-22 crank angle sensor connector, and measure at the pick-up harness.
  • Engine: Idling
  • Transmission: P range
  • Voltage between terminal No. 3 and earth.
<Camshaft position sensor>
  • Use the test harness (MB991709) to connect B-101 camshaft position sensor connector, and measure at pick-up harness.
  • Engine: Idling
  • Transmission: P range
  • Voltage between terminal No. 3 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 on timing belt.

STEP 6. Check crank shaft sensing ring.

Q. Is the check result normal?
Go to Step 7 .
Replace the crank shaft sensing ring.

STEP 7. Check camshaft position sensing cylinder.

Q. Is the check result normal?
Go to Step 8 .
Replace the camshaft position sensing cylinder.

STEP 8. Replace the crank angle sensor.

  • After replacing the crank angle sensor check for the trouble symptom again.

Q. Does the trouble symptom persist?
Go to Step 9 .
Check end.

STEP 9. Replace the camshaft position sensor.

  • After replacing camshaft position sensor check for the trouble symptom again.

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 ).