P0340

DTC P0340

Circuit Description

The camshaft position (CMP) sensor is a 1X sensor. The CMP provides one digital ON/OFF signal to the powertrain control module (PCM) per revolution of the camshaft. This information is used by the PCM to determine the position of the valve train relative to the crankshaft position (CKP). By monitoring the CMP and CKP signals, the PCM can accurately time the operation of the fuel injectors. The CMP sensor is connected directly to the ignition control module (ICM). The sensor wiring includes the following circuits which are shared with the CKP sensor:

* The CMP sensor signal circuit
* A 12-volt reference circuit
* A low reference circuit

The signal is passed through the ICM to the PCM on the camshaft position signal circuit. The PCM monitors the CMP sensor for errors. If the PCM does not receive a signal from the CMP sensor, DTC P0340 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0340 Camshaft Position (CMP) Sensor Circuit

Conditions for Running the DTC

* The engine is cranking.
OR
* The engine is running for more than 3 seconds.
* This diagnostic runs continuously when either condition is met.

Conditions for Setting the DTC

* The PCM detects the following for every 2 engine revolutions:

- 36 medium resolution engine speed signals
- 6 low resolution engine speed signals
- 0 camshaft position signals

* The condition exists for more than 4 seconds.

Action Taken When the DTC Sets

* The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

* The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

Inspect for the following conditions:

* Any secondary ignition wires arcing to a wiring harness and for carbon tracking or other signs of damage
* A faulty ignition coil
* The ignition control module and the coils for cracks, carbon tracking, or other signs that indicate that the coil secondary circuit is arcing to the ICM or to the ICM wiring harness-Refer to Ignition Coil Replacement.

If the condition is suspected of being intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

Test Description

Step 1 - Step 8:

Step 9 - Step 17:

Step 18 - Step 30:

Step 31 - Step 32:

The numbers below refer to the step numbers on the diagnostic table.
14. This test verifies if the sensor is working correctly. By suppling a ground to the circuit, the voltage should change when the circuit is touched with a test lamp.
26. This step determines if the fault is caused by a missing camshaft magnet or by a faulty PCM. The voltage measured in this step should be near 5 volts, and decrease to near 0 volts when the CMP sensor interfaces with the camshaft magnet.