P0340

CIRCUIT DESCRIPTION
The powertrain control module (PCM) uses the camshaft position (CMP) sensor high resolution signal to determine the position of the valve train in relation to the engine cylinders. The PCM uses the CMP high resolution signal 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, diagnostic trouble code (DTC) P0340 will set.

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

CONDITIONS FOR SETTING THE DTC
The PCM detects a loss of the 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
If the condition is intermittent, refer to Intermittent Conditions. Intermittent Conditions

Ignition system DTCs set with the ignition switch in the START position if the starter relay or the starter is inoperative. When the PCM enables starter operation, the PCM also initiates the diagnostic test routines for DTCs P0335, P0340, and P0385. If a condition exists which prevents the engine from cranking, the PCM will not receive signal input from the CKP and CMP sensors, and the DTCs will set.

If DTC P0615 is set, diagnose DTC P0615 first. If DTC P0335, P0340, and/or P0385 are set and no trouble is found, check for the following:
^ Is there a no-crank condition or an intermittent no-crank condition?
^ Was an attempt made to crank the engine with the shift lever not in P/N?

TEST DESCRIPTION

Steps 1-9:

Steps 10-18:

The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the 12-volt reference circuit to the crankshaft position (CKP) A, CKP B, and the camshaft position (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 three DTCs set because the 12-volt reference circuit are internally connected within the PCM. The engine will not start with this condition.
9. 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.
10. 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.
11. 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.