Exhaust Camshaft Position Sensor and Crankshaft Position Sensor
EXHAUST CAMSHAFT POSITION SENSOR AND CRANKSHAFT POSITION SENSORRequired Special Tools:
- MB991709: Test Harness
- MB992110: Power Plant ECU Check Harness
Measurement Method
1. Disconnect the exhaust camshaft position sensor connector, and connect the test harness special tool (MB991709) between the separated connector (All terminals should be connected).
2. Connect the oscilloscope probe to exhaust camshaft position sensor connector terminal No. 3.
3. Disconnect the crankshaft position sensor connector, and connect the test harness special tool (MB991709) between the separated connector.
4. Connect the oscilloscope probe to crankshaft position sensor connector terminal No. 3.
Alternate method
1. Disconnect all ECM connectors. Connect the check harness special tool (MB992110) between the separated connectors.
2. Connect the oscilloscope to check harness terminal No. 7. (Check the exhaust camshaft position sensor signal wave pattern.)
3. Connect the oscilloscope to check harness terminal No. 8. (Check the crankshaft position sensor signal wave pattern.)
Wave Pattern Observation Points
- Verify that, toward the engine speed of 2,500 r/min, time difference T from when the crankshaft position sensor output wave falls to when the exhaust camshaft position sensor output wave falls becomes less.
Examples of Abnormal Wave Patterns
Example 1
Cause of problem
- Sensor interface malfunction
Wave pattern characteristics
- Rectangular wave pattern is output even when the engine is not started.
Example 2
Cause of problem
- Loose timing belt.
- Abnormality in sensor disc.
Wave pattern characteristics
- Wave pattern is displaced to the left or right.