Camshaft Position Sensor
The Camshaft Position (CMP) sensors are located in the camshaft carriers and are secured with a screw. Both CMP sensors extend into the camshaft carriers and are sealed with O-ring seals. When the reluctor ring is repeatedly moved over the CMP sensors, a voltage will be created by the CMP sensors. The CMP sensors measure the magnetic field variation induced by the reluctor ring. The CMP sensors are Hall effect sensors which produce a square wave signal, the frequency of which is proportional to engine speed.
The CMP sensors receive a 5V reference voltage from the Powertrain Control Module (PCM). A further 2 connections to the PCM provide ground and signal output. The PCM uses the signal from the CMP sensors and the Crankshaft Position (CKP) sensor to determine current intake and exhaust camshaft position and camshaft adjustment.
If a fault occurs with any of the CMP sensors, a Diagnostic Trouble Code (DTC) is registered in the PCM.
The following 2 types of failure can occur:
- Camshaft signal frequency too high.
- Total failure of the camshaft signal.
The DTC recorded by the PCM can also relate to a total failure of the crankshaft signal or crankshaft signal dynamically implausible. Both components should be checked to determine the cause of the fault.
If a fault occurs with any of the CMP sensors when the engine is running, the engine will continue to run. Once the engine is switched off, the engine will crank and restart while the fault is present, but Variable Camshaft Timing (VCT) control will be disabled.