P0340

CIRCUIT DESCRIPTION
The powertrain control module (PCM) uses the camshaft position (CMP) sensor high resolution signal in order to determine the position of the valve train in relation to the engine cylinders. The PCM uses the CMP high resolution signal in order to sequence the ignition system and the fuel injectors.

The PCM supplies a 12-volt reference and a low reference to the CMP sensor. The CMP sensor returns a signal pulse in response to the reluctor track, located on the camshaft sprocket. If during operation, the PCM detects a loss of CMP sensor high resolution signal, DTC P0340 will set.

CONDITIONS FOR RUNNING THE DTC
No CKP sensor DTCs set with the engine running more than 400 RPM.

CONDITIONS FOR SETTING THE DTC
The PCM detects a loss of CMP sensor high resolution signal.

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
- The following conditions may cause this DTC to set:
- Damage to the camshaft sprocket
- Incorrect sensor installation
- The sensor coming in contact with the camshaft sprocket
- Excessive air gap between the camshaft sprocket and the sensor
- A cracked or damaged sensor
- Foreign material passing between the sensor and the sprocket
- If the condition is intermittent, refer to Computers and Controls Systems Schematics .

TEST DESCRIPTION

Steps 1-4:

Steps 5-6:

Steps 7-10:

Steps 11-17:

Steps 18-22:

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the 12-volt reference circuit to the CKP A, the CKP B, and the CMP is shorted to a ground. If all 3 DTCs are set, this indicates the circuit is shorted to a ground or a sensor is internally shorted. All 3 DTCs set because the 12-volt reference circuit is internally connected within the PCM. The engine will not start with this condition.
8. This step determines if the CMP sensor is shorted internally. If the 12-volt reference parameter changes from Fault to OK, the condition is with the sensor.
9. This step determines if the CKP A sensor is shorted internally. If the 12-volt reference parameter changes from Fault to OK, the condition is with the sensor.
10. This step determines if the CKP B sensor is shorted internally. If the 12-volt reference parameter changes from Fault to OK, the condition is with the sensor.