Diagnostic Instructions

DTC Descriptor

DTC P0340: Camshaft Position (CMP) Sensor Circuit

DTC P0341: Camshaft Position (CMP) Sensor Performance

DTC P0342: Camshaft Position (CMP) Sensor Circuit Low Voltage

DTC P0343: Camshaft Position (CMP) Sensor Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
CMP Sensor 5 Volt Reference	P0340, P0341, P0342, P0455, P0489	P0342, P0343	--	P0341
CMP Sensor Signal	P0342	P0343	P0343	P0341
Low Reference	--	P0343	--	P0341

Circuit/System Description

The camshaft position (CMP) sensor correlates the crankshaft to camshaft position so that the engine control module (ECM) can determine which cylinder is ready to be fueled by an injector. As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor and sends a signal to the ECM through the signal circuit. The CMP sensor circuits are directly connected to the ECM. The CMP sensor also determines which cylinder is misfiring. The CMP sensor circuits consist of the following:

Conditions for Running the DTC

Conditions for Setting the DTC

P0340

The ECM detects no pulses from the CMP sensor.

P0341

The ECM detects that the CMP sensor signal voltage is erratic.

P0342

The ECM detects that the CMP sensor signal voltage is always low and the ECM detects no pulses from the CMP sensor.

P0343

The ECM detects that the CMP sensor signal voltage is always high and the ECM detects no pulses from the CMP sensor.

Action Taken When the DTC Sets

DTCs P0340, P0341, P0342, and P0343 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0340, P0341, P0342, and P0343 are Type B DTCs.

Diagnostic Aids

The following conditions can also set the DTC:

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electronic Ignition (EI) System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Engine running, observe the DTC information with a scan tool. DTCs P0340, P0341, P0342, and P0343 should not set.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. 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, and the MAIN fuse removed, disconnect the harness connector at the CMP sensor.

Notice: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.

Important: The control module or the sensor may be damaged if the circuit is shorted to B+ voltage.

2. Test for 10 ohms of resistance between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the ECM.

3. Install the MAIN fuse. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 1 and ground.

⇒	If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.

⇒	If greater than the specified range, test the 5 volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Test for 10-12 volts between the signal circuit terminal 3 and ground.

⇒	If less than the specified range, test signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

5. Verify that a test lamp does not illuminate between the signal circuit terminal 3 and ground.

⇒	If the test lamp does not illuminate, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

6. If all circuits test normal, test or replace the CMP sensor.

Repair Instructions

Perform the Perform the Diagnostic Repair Verification after completing the diagnostic procedure.