Crankshaft Position Sensor: Testing and Inspection

NOTE: Proper testing of the Crankshaft Position Sensor involves testing the Camshaft Position Sensor also.




WAVE PATTERN INSPECTION WITH ANALYZER
1. Disconnect the connector of the camshaft position sensor, and connect the special tool (test harness: MB991348) across the disconnected connector parts. (Connect the tool to all terminals.)

2. Connect the special patterns pickup of the analyzer to the terminal (1) of the distributor connector (in order to inspect the signal waveform of the camshaft position sensor).

3. Connect the special patterns pickup of the analyzer to the terminal (2) of the crankshaft position sensor connector (in order to inspect the signal waveform of the crankshaft position sensor).

Alternative Connection Method (when Special Harness is not available)
1. Connect the analyzer special patterns pickup to ECM terminal (68) for the camshaft position sensor.
2. Connect the analyzer special patterns pickup to ECM terminal (69) for the crankshaft position sensor.


STANDARD WAVE PATTERN



Observation conditions set to the following:
Function: Special patterns
Pattern height: Low
Pattern selector: Display
Engine rpm: Idling (700 rpm)

Wave pattern observation points
Check that cycle time "T" becomes shorter and the frequency increases when the engine speed is increased.

EXAMPLES OF ABNORMAL WAVE PATTERNS




Cause of problem: Malfunction of sensor interface
Wave pattern characteristics: Short wave pattern is output even when the engine is not started.




Cause of problem: Loose timing belt/Abnormality in sensor disk
Wave pattern characteristics: Wave pattern is displaced to the left or right.