Diagnostic Instructions

DTC Descriptors

DTC P0341: Intake Camshaft Position (CMP) Sensor Performance Bank 1

DTC P0346: Intake Camshaft Position (CMP) Sensor Performance Bank 2

DTC P0366: Exhaust Camshaft Position (CMP) Sensor Performance Bank 1

DTC P0391: Exhaust Camshaft Position (CMP) Sensor Performance Bank 2

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5-Volt Reference Circuit	P0069, P0107, P0340, P0345, P0365, P0390, P0452, P0522, P0532, P0641, P1183, P2228	P0340, P0345, P0365, P0390	P0641	--
CMP Sensor Signal Circuit	P0340, P0345, P0365, P0390	P0340, P0345, P0365, P0390	P0340, P0345, P0365, P0390	P0341, P0346, P0366, P0391
Low Reference Circuit	--	P0340, P0345, P0365, P0390	P0340, P0345, P0365, P0390	--

Circuit/System Description

The 4X camshaft position (CMP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CMP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 4-tooth reluctor wheel attached to the camshaft. As each reluctor wheel tooth rotates past the CMP sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency, with 2 narrow, and 2 wide output pulses per camshaft revolution that represent an image of the camshaft reluctor wheel. The frequency of the CMP sensor output depends on the velocity of the camshaft. The ECM decodes the narrow and wide tooth pattern to identify camshaft position. This information is then used to determine the optimum ignition timing and fuel injection points of the engine. The ECM also uses CMP sensor output information to determine the camshaft relative position to the crankshaft, to control the CMP actuator if equipped, and for limp-home operation.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the DTC

DTCs P0341, P0346, P0366, P0391 are Type B DTCs.

Diagnostic Aids

With a DTC set, the engine may crank for an extended period of time during start-up.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electronic Ignition (EI) System Diagnosis

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 35616 Connector Test Adapter Kit

Circuit/System Verification

1. Ignition OFF, inspect the engine wiring harness carrying the CMP sensor circuits for the following conditions:

•	Close routing of aftermarket electrical equipment

•	Close to solenoids, motors, and relays

⇒	Correct any wire harness routing or component placement conditions, if it is determined to be a possible source of electrical interference.

2. Observe that the following parameters are all incrementing:

•	Exhaust CMP bank 1 active

•	Intake CMP bank 1 active

•	Exhaust CMP bank 2 active

•	Intake CMP bank 2 active

3. Engine running, observe the DTC information with a scan tool. DTCs P0340, P0341, P0345, P0346, P0365, P0366, P0390, or P0391 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, inspect the CMP sensor for correct installation.

⇒	If the CMP sensor is loose, inspect the sensor and the O-ring for damage, replace as necessary.

2. Inspect the engine for the following conditions:

•	Engine oil for debris

•	Camshaft reluctor wheel for damage

•	The timing chain, tensioner and sprockets for wear or damage

⇒	If debris is found in the engine oil, inspect the internal engine components to determine the root cause. Repair or replace any worn or damaged components.

Component Testing

Important: You must perform the Circuit/System Testing before proceeding with Component Testing.

1. Inspect the CMP sensor for correct installation. Remove the CMP sensor from the engine and inspect the sensor O-ring for damage.

⇒	If the sensor is loose, incorrectly installed, or damage, replace the CMP sensor.

2. Connect the CMP sensor harness connector to the CMP sensor.
3. Ignition ON, engine OFF. Observe the CMP Active Counter parameter on the scan tool.
4. Pass a flat steel object repeatedly across the tip of the sensor that faces the reluctor wheel. The CMP Active Counter parameter should increment with each pass of the steel object.

⇒	If the parameter does not increment, replace the CMP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.