Circuit Description
The exhaust camshaft position (CMP) sensor is a hall integrated circuit (IC) type sensor that works in conjunction with a single tooth reluctor wheel used to determine the position of the exhaust camshaft. The engine control module (ECM) supplies a 12-volt pull up voltage on the CMP sensor signal circuit. As the tooth on the reluctor wheel passes the CMP sensor, it sends a digital signal which is an image of the reluctor wheel, to the ECM. The ECM processes this information to determine the exact position of the camshafts, and to determine the optimum ignition and injection points of the engine. The CMP sensor wiring consists of a 12-volt reference circuit, a low reference circuit, and a signal circuit. If the ECM detects extra or missing CMP sensor signal transitions within a certain number of crankshaft revolutions, DTC P0336 or P0391 will set.