Camshaft Position Sensor: Testing and Inspection
CMPSCMPS:
The camshaft position sensor senses the position of crankshaft (piston) in reference to the upper dead point of compression of each cylinder and send the signal, based on which the ECM computes the engine speed and controls the fuel injection timing and ignition timing. Engine running condition (idle, partial load and full load) is determined in this process. It outputs digital signal by two hall devices.
Circuit Diagram And Signal Features:
In case of faulty CMP, the TDC signal is analyzed to computing the crank position and engine rpm to further control the fuel quantity and ignition timing. Engine running is available at the same time. There is no engine stall at faulty CMP like existing system. (When the CMP is failed during engine running, the engine stalls, but restart of engine is available by the procedures of operation as IG KEY OFF -> ON.)
Troubleshooting hints
1. If an unexpected shock or engine stall occurs in running, try to shake the harness of crankshaft position sensor. Check the sensor connector(s) for defective contacts if engine stalls in the case.
2. If 0 rpm is indicated on tachometer with the engine in idling, check for faulty crankshaft angle sensor, damaged timing belt or faulty ignition system.
3. Check for the points as below if the crankshaft angle sensor indicates a value out of the specification though the engine is available of starting in idle.
- Faulty engine coolant temperature sensor.
- Faulty idle speed control motor.
- Failed standard idle speed control.