Camshaft Position Sensor (3.8L)
The 3.8L C3 I system uses a 3-wire, Hall Effect switch Camshaft Position (CMP) sensor mounted on timing cover behind the water pump. As camshaft sprocket rotates, the Hall Effect switch alternately grounds and opens a 12-volt signal circuit to the ignition module. The constant grounding and opening of this circuit results in a toggling on/off signal which is interpreted by ignition module as a TDC No. 1 compression signal. The ignition module passes this signal on to the PCM. The camshaft signal, in conjunction with 3X and 18X crankshaft signals, allows PCM to properly time ignition and fuel injection. Also see CRANKSHAFT (3X/18X) SENSOR (3.8L) .
If sensor should fail while engine is running, engine will continue to run using the last calculated CMP sensor signal to maintain sequential fuel injection mode. Upon restart, engine will run with a 1-in-6 chance of being correct. When incorrect, engine will run rough. For additional information, see COMPUTER CONTROLLED COIL IGNITION (C3I) under IGNITION SYSTEM.