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VIN 6




DTC P0340

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provide an overview of each diagnostic category.

DTC Descriptor
DTC P0340
- Camshaft Position (CMP) Sensor Circuit

Diagnostic Fault Information





Typical Scan Tool Data





Circuit/System Description

The hall effect camshaft position (CMP) sensor produces 3 ON/OFF pulses for each revolution of the camshaft. The CMP output is pulse width encoded. The engine control module (ECM) uses the CMP and crankshaft position (CKP) output pulses to determine the engine speed and position. The CMP is connected directly to the ECM by the following circuits:

* The 5-volt reference circuit
* The low reference circuit
* The CMP sensor signal circuit

Conditions for Running the DTC

* The ignition is ON.
* The engine is turning faster than 50 RPM.
* DTC P0340 runs continuously when the above conditions are met.
* DTCs P0335, P0336, P0642, or P0643 are not set.

Conditions for Setting the DTC

The ECM does not see a CMP sensor signal for more than 2 seconds.

Action Taken When the DTC Sets

DTC P0340 is a Type A DTC.

Conditions for Clearing the MIL/DTC

DTC P0340 is a Type A DTC.

Diagnostic Aids

If the CMP sensor signal is lost while running, the engine will operate normally. If the CMP sensor signal is not present on start-up, the engine will not start.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

J 38522 Variable Signal Generator

Circuit/System Verification

1. If DTCs P0642 or P0643 are set, diagnose those DTCs first.
2. Engine running, observe the DTC information with a scan tool. DTC P0340 should not set.
3. 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 and scan tool disconnected for 90 seconds, disconnect the harness connector at the CMP sensor.
2. Test for less than 5 ohms between low reference circuit terminal 2 of the connector and ground.

• If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 of the connector and ground.

• If less that the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
• 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. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal 1 of the connector and ground.

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

5. Ignition OFF, connect a 3-amp fused jumper wire between signal circuit terminal 1 of the connector and ground.
6. Ignition ON, observe the scan tool 5-Volt Reference 1 Circuit Status parameter. The parameter should display OK.

• If the 5-Volt Reference 1 Circuit Status parameter does not display OK, test the signal circuit for a short to 5-volt reference. If the circuit tests normal, replace the ECM.

7. Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal 1 of the connector. Connect the battery voltage supply to B+. Connect the black lead to ground.
8. Set the J 38522 signal switch to 5 volts, the frequency to 60, and the Duty Cycle to Normal.
9. Ignition ON, observe the CMP Sensor Signal Present parameter of the scan tool. The parameter should display YES.

• If the parameter does not display YES, replace the ECM.

10. If the circuits test normal, replace the CKP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Camshaft Position Sensor Replacement (Service and Repair)
* Camshaft Position Sensor Exciter Ring Replacement (Camshaft Position Sensor Exciter Ring Replacement)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming

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