P0340

DTC P0340

CIRCUIT DESCRIPTION
The camshaft position (CMP) sensor is installed on the cylinder head at the rear of the camshaft gear. The CMP sensor has the following circuits.
- 12 volts feed circuit
- CMP sensor signal circuit
- CMP sensor shield circuit

The engine control module (ECM) supplies 12 volts to the CMP sensor on the 12 volts feed circuit. The CMP sensor provides a signal to the ECM on the CMP signal circuit. The CMP sensor detects a total of five through holes (four holes arranged equally every 90° and one reference hole on the camshaft gear flange surface) and sends signals to the engine control module (ECM). Receiving these signals, the ECM determines cylinder #1 compression top dead center (TDC). If the ECM detects that CMP sensor signals are not generated, this DTC will set.

Condition for Running the DTC
- The battery voltage is between 10-16 volts.
- The crankshaft position (CKP) sensor signal pulse is detected.

Condition for Setting the DTC
- The ECM detects that the CMP sensor pulses are not generated during 10 engine rotations.

Action Taken When the DTC Sets
- The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Freeze Frame/Failure Records.

Condition for Clearing the MIL/DTC
- The ECM turns OFF the MIL after 3 consecutive driving cycles when the diagnostic runs and does not fail. (12,000 lbs GVW)
- The ECM turns OFF the MIL when the diagnostic runs and does not fail. (Except 12,000 lbs GVW)
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes after the key is cycled.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic after the ECM turns OFF the MIL.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
If an intermittent condition is suspected, the following may cause an intermittent:
- Poor connections
- Misrouted harness
- Rubbed through wire insulation
- Broken wire inside the insulation

Check for the following conditions:
- Poor connection at the ECM: Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness: Inspect the wiring harness for damage. If the harness appears to be OK, observe the "Cam Signal Present" display on the scan tool with the engine running while moving connectors and the wiring harness related to the sensor. A change in the display will indicate the location of the fault.

DTC P0340
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

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