Friday, February 24, 2012

Camshaft Position CMP Sensor Operation?

The details are as follows :---

Camshaft Position (CMP) Sensor

OPERATION


The PCM uses the Camshaft Position (CMP) sensor signal to determine the position of the No. 1 cylinder piston during its power stroke. The signal is used by the PCM to calculate fuel injection mode of operation. If the cam signal is lost while the engine is running, the fuel injection system will shift to a calculated fuel injected mode based on the last fuel injection pulse, and the engine will continue to run.

On the 3.1L and 3.4L (VIN E) engine, the Camshaft Position (CMP) sensor is located on the timing chain cover behind the water pump near the camshaft sprocket. As the camshaft sprocket turns, a magnet in it activates the Hall-Effect switch in the CMP sensor. When the Hall-Effect switch is activated, it grounds the signal line to the PCM, pulling the CMP sensor circuit's applied voltage low. This is interpreted as a CAM signal. The cam signal is created as piston #1 is on the intake stroke. If the correct CAM signal is not received by the PCM, a DTC will be set.

On the 3.4L (VIN X) engine, the Camshaft Position (CMP) sensor is mounted to the left bank camshaft carrier, towards #6 cylinder. A 3-wire harness connector plugs into the sensor, connecting it to the Powertrain Control Module (PCM). The PCM applies a signal voltage to the sensor. The left bank exhaust camshaft has a tooth machined into the casting. The camshaft position sensor is separated from the exhaust camshaft by an air gap. As the exhaust camshaft rotates, the machined tooth aligns with the sensor. The signal voltage to the sensor is pulled low. The PCM interprets the change in signal voltage as an indication of camshaft position. The CAM signal is created as piston #1 is on the intake stroke. If the correct CAM signal is not received by the PCM, a DTC will set.

On the 3.5L (VIN H) engine, the Camshaft Position (CMP) sensor is located at the rear of the forward camshaft carrier, near the engine lift ring bracket. The sensor signal, when combined with the Crankshaft Position sensor signal, enables the PCM to determine exactly which cylinder is on a firing stroke. The PCM can then properly synchronize the ignition system, fuel injectors and knock control. The camshaft position sensor has a power, ground and signal circuit. The PCM supplies 12 volts to the sensor. The PCM also supplies the ground path, or sensor return circuit, from the sensor. These power and ground circuits are also connected to the crankshaft position sensor. If a problem is detected in the camshaft position circuit, a DTC will set.

On 3.8L engine, the Camshaft Position (CMP) sensor is mounted on the engine timing chain front cover. The camshaft position sensor sends a cam signal to the PCM which uses it as a sync pulse to trigger the injectors in the proper sequence. The CAM signal is passed through the ignition control module. The PCM uses the CAM signal to indicate the position of the #1 piston during its power stroke, allowing the PCM to calculate true Sequential Fuel Injection. If the PCM detects an incorrect CAM signal, a DTC will set.


This will help.
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