Crankshaft Position Sensor: Testing and Inspection

CAMSHAFT POSITION SENSOR AND CRANKSHAFT POSITION SENSOR

Required Special Tools:
MB991709: Test Harness Set
MB998478: Test Harness

Measurement Method




1. Disconnect the camshaft position sensor connector, and connect the test harness special tool (MB991709) in between. (All terminals should be connected.)
2. Connect the oscilloscope probe to camshaft position sensor connector terminal No. 2.




3. Disconnect the crankshaft position sensor connector, and connect the test harness special tool (MD998478) in between.
4. Connect the oscilloscope probe to crankshaft position sensor connector terminal No. 2. (black clip of special tool).

Alternate method (Test harness not available)
1. Connect the oscilloscope probe to ECM terminal No. 88. (Check the camshaft position sensor signal wave pattern.)
2. Connect the oscilloscope probe to ECM terminal No. 89. (Check the crankshaft position sensor signal wave pattern.)







Standard Wave Pattern

Wave Pattern Observation Points
Check that cycle time T becomes shorter when the engine speed increased.

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.