Oscilloscope Patterns and Waveforms

INSPECTION
Wave Pattern Inspection using an Analyzer Measurement method
(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 (2) of the camshaft position sensor connector.
(3) Disconnect the connector of the crankshaft position sensor, and connect the special tool (test harness: MD998478) across the disconnected connector parts.
(4) Connect the special patterns pickup of the analyzer to the terminal (2) of the crankshaft position sensor connector.

Alternative method (when test harness is not available)
(1) Connect the analyzer special patterns pickup to ECM terminal (88) for the camshaft position sensor.
(2) Connect the analyzer special patterns pickup to ECM terminal (89) for the crankshaft position sensor.




Standard wave pattern
Observation conditions




Standard wave pattern

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
- Example 1
Cause of problem
Malfunction of sensor interface

Wave pattern characteristics
Short wave pattern is output even when the engine is not started.




- Example 2
Cause of problem
Loose timing belt
Abnormality in sensor disk

Wave pattern characteristics
Wave pattern is displaced to the left or right.