Grand Prix V6-191 3.1L VIN M SFI (1998)
Camshaft Position Sensor: Description and Operation
DESCRIPTION
The camshaft position sensor is located on the timing cover behind the water pump near the camshaft sprocket.
OPERATION
As the camshaft sprocket turns, a magnet in it activates the Hall-effect switch in the camshaft position sensor. When the Hall-effect switch is activated,
it grounds the signal line to the PCM, pulling the camshaft position sensor signal circuit's applied voltage low. This is interpreted as a CAM signal.
The camshaft position sensor sends a cam signal to the PCM which uses it as a sync pulse to trigger the injectors in proper sequence. The PCM uses
the CAM signal to indicate the position of the #1 piston during its intake stroke. This allows the PCM to calculate true Sequential Fuel Injection (SFI)
mode of operation.
If the CAM 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. The engine can be restarted and will run in the calculated sequential mode as long as the fault
is present with a 1 in 6 chance of injector sequence being correct. Refer to DTC P0341 for further information. See: Computers and Control
Systems/Testing and Inspection
