Pinpoint Test G: Camshaft Position Sensor: Description
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Camshaft Position (CMP) sensor is a Hall-effect type sensor that generates a digital frequency, as windows in a target wheel pass through its magnetic field. Frequency of windows passing by sensor as well as width of selected windows allows Powertrain Control Module (PCM) to detect engine speed and position. DTC 0340 indicates CMP sensor circuit malfunction. DTC 0341 indicates CMP sensor circuit performance. DTC 0344 indicates CMP sensor circuit intermittent.
- Engine Speed
Is determined by counting 12 windows on cam gear each camshaft revolution. - Fuel Timing Control
Position of cylinders No. 1 and No. 4 is determined by distinguishing a narrow or wide window on camshaft gear. - Engine Mode Selection
Allows PCM to discern when engine is in off, crank or run mode. - Injection Control Pressure
Engine speed is one of the controlling variables in calculation of desired injection control pressure. - Exhaust Back Pressure
Exhaust back pressure control is a function of engine speed and load. - Fuel Quantity Control/Torque Limiting
Engine torque and fuel is controlled and is dependent on engine speed. Fuel quantity is determined by engine speed. - Detection/Management
An inactive CMP signal during cranking is detectable by PCM. An inactive CMP signal will cause a no-start condition. Electrical noise can also be detected by PCM. If level is sufficient to effect engine operation, a corresponding DTC will be set.
Perform this test when directed here by QUICK TEST. This PINPOINT TEST is intended to diagnose:
- Camshaft Position (CMP) sensor.
- Wiring harness circuits; (CMP GND, VREF and CMP Signal).
- Powertrain Control Module (PCM).