Camshaft Position Sensor: Testing and Inspection
CAMSHAFT POSITION SENSOR AND CRANKSHAFT POSITION SENSORRequired Special Tools:
MB991709: Test Harness Set
MB991658: Test Harness Set
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 2.
3. Disconnect the crankshaft position sensor connector, and connect the test harness special tool (MB991658) in between. (All terminals should be connected.)
4. Connect the oscilloscope probe to crankshaft position sensor connector terminal 3.
Alternate method (Test harness not available)
1. Connect the oscilloscope probe to ECM terminal 88. (Check the camshaft position sensor signal wave pattern.)
2. Connect the oscilloscope probe to ECM terminal 89. (Check the crankshaft position sensor signal wave pattern.)
1. Connect the oscilloscope probe to PCM terminal 56. (Check the camshaft position sensor signal wave pattern.)
2. Connect the oscilloscope probe to PCM terminal 45. (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.