Inspection Procedure 15: Ignition Timing Offset

COMMENT ON TROUBLE SYMPTOM

Failure is possibly caused by failed crank angle sensor, camshaft position sensor, or timing belt in out of place and so on.

PROBABLE CAUSE

Failed crank angle sensor
Failed camshaft position sensor
Timing belt in out of place
Failed engine-A/T-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 of crank angle sensor and camshaft position sensor (Using an oscilloscope).

Crank Angle Sensor

Use special tool test harness (MB991658) to connect B-121 crank angle sensor intermediate connector, and measure at pick-up harness.
Engine: Idling
Transmission: P range
Voltage between terminal No. 2 and earth.

Camshaft Position Sensor

Use special tool test harness (MB991709) to connect B-114 camshaft position sensor connector, and measure at pick-up harness.
Engine: Idling
Transmission: P range
Voltage between terminal No. 2 and earth.

OK: Output waveform timings of both sensors are the same as the check procedure (Refer to ) using an oscilloscope.

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 engine-A/T-ECU.

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

STEP 4. Check crank angle sensor and camshaft position sensor mounted conditions.

Q. Is the check result normal?

	Go to Step 5 .

	Repair.

STEP 5. Check timing marks of timing belt.

Q. Is the check result normal?

	Go to Step 6 .

	Align timing marks.

STEP 6. Check crank shaft sensing blade.

Q. Is the check result normal?

	Go to Step 7 .

	Replace crank shaft sensing blade.

STEP 7. Check camshaft position sensing cylinder.

Q. Is the check result normal?

	Go to Step 8 .

	Replace camshaft position sensing cylinder.

STEP 8. Replace crank angle sensor.

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

Q. Does the trouble symptom persist?

	Go to Step 9 .

	Check end.

STEP 9. Replace camshaft position sensor.

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

Q. Does the trouble symptom persist?

	Replace engine-A/T-ECU.

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