Ignition Timing: Description and Operation

Camshaft Position (CMP) Sensor And Signal




The camshaft position (CMP) sensor sends a signal to the PCM. The PCM uses this signal as a "sync pulse" to trigger the injectors in the proper sequence. The PCM uses the CMP signal to indicate the position of the #1 piston during its power stroke. The CMP allows the PCM to calculate true sequential fuel injection (SFI) mode of operation. If the PCM detects an incorrect CMP signal while the engine is running, DTC P0341 will set.

If the CMP signal is lost while the engine is running, the fuel injection system will shift to a calculated sequential fuel injection mode based on the last fuel injection pulse, and the engine will continue to run. It will run in the calculated sequential mode with a 1-in-4 chance of the injector sequence being correct.

For further information, refer to DTC P0341 and DTC P0342.

CMP Signal
The PCM uses the camshaft position (CMP) sensor signal to determine the position of the number 1 piston during its power stroke, allowing the PCM to calculate true sequential multiport fuel injection (SFI). Loss of this signal will set a DTC P0341 or DTC P0342.

If the CMP signal is lost while the engine is running, the fuel injection system will shift to a calculated sequential fuel injection based on the last fuel injection pulse, and the engine will continue to run. The engine can be restarted and will run in the calculated sequential mode with the fault is present, with a 1-in-4 chance of being correct.