P0340

Circuit Description
The Camshaft Position (CMP) Sensor works in conjunction with a single tooth reluctor wheel on the Bank 2 Intake camshaft. The ECM pulls up the CMP sensor signal circuit to 5 volts and monitors this voltage. As the reluctor wheel tooth rotates past the sensor, the sensor's internal circuitry pulls the signal circuit to ground, creating a square wave signal that is used by the ECM. The reluctor wheel tooth covers 180 degrees of the camshaft circumference. This causes the CMP signal voltage to transition once per crankshaft revolution. This signal, when combined with the CKP sensor signal, enables the ECM to determine exactly which cylinder is on a firing stroke. The ECM can then properly synchronize the ignition system, the fuel injectors and the knock control. Note that as long as the CKP signal is available, the engine can start even if there is no CMP sensor signal. The ECM will default to a non-sequential fuel injector operation.

Conditions for Running the DTC
The engine speed is greater than 20 RPM.

Conditions for Setting the DTC
The CMP signal is incorrect for at least 5 cycles.

Action Taken When the DTC Sets
^ The ECM illuminates the Malfunction Indicator Lamp (MIL) and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.
^ The ECM will use a calculated spark retard value in order to minimize a knock during conditions when a knock is likely to occur. The calculated value will vary based on the engine speed and load.

Conditions for Clearing the MIL/DTC
^ The ECM turns off the MIL after three consecutive drive trips that the diagnostic runs and passes.
^ A History DTC clears after forty consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic.
^ The ECM battery voltage is interrupted.
^ The scan tool clears the MIL/DTC.

Diagnostic Aids

Notice: Refer to J 35616-A Connector Test Adapter Kit Notice in Service Precautions.

Use the J 35616-A Connector Test Adapter kit for any test that requires probing the ECM harness connector or a component harness connector.

Check for the following conditions:
^ Poor connections at the ECM or at the component-Inspect the harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
^ Misrouted harness-Inspect the harness in order to ensure that the harness is not routed too close to any high voltage wires such as spark plug leads, or too close to any high current devices such as the alternator, the motors, the solenoids, etc.
^ Damaged harness-Inspect the wiring harness for any damage. If the harness appears to be OK, observe the scan tool while moving the related connectors and the wiring harnesses. A change in the display may help in order to locate the fault.
If the sensor signal is only affected when the harness is moved at a component, and there is no problem with the harness or the connections, the component may be damaged.
^ Check the sensor for a proper installation. A sensor that is loose or not fully seated (causing an excessive air gap between the sensor and the reluctor wheel) may cause this DTC to set.

Refer to Symptoms for the intermittents. Symptom Related Diagnostic Procedures

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This step checks for proper switched B+ to the sensor.
4. This step checks for a proper ground to the sensor.
5. This step checks for the proper ECM pull-up voltage to the sensor.
6. This step checks if the CMP sensor can produce a signal to the ECM.