P0340

DTC P0340

CIRCUIT DESCRIPTION
This ignition system does not use a conventional camshaft position (CMP) sensor that detects valve train position. The ignition control module (ICM) detects when the #1 or #3 cylinder has fired on the cylinders compression stroke using sensing circuitry integrated within each coil. The sensing circuit detects the polarity and the strength of the secondary voltage output. The higher output is always at the event cylinder. The ICM sends a CMP signal to the engine control module (ECM) based on the voltage difference between the event and waste cylinder firing energy. This system is called compression sense ignition. By monitoring the CMP and crankshaft position (CKP) signals, the ECM can accurately sequence the fuel injectors. If the ECM does not receive a CMP signal from the ICM, DTC P0340 sets.

CONDITIONS FOR RUNNING THE DTC
- The engine is running.
- The manifold absolute pressure (MAP) is more than 30 kPa.

CONDITIONS FOR SETTING THE DTC
The ECM does not detect any change in the CMP sensor signal for 107 crankshaft revolutions when the MAP is at 30 kPa or more.

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
- An intermittent crank signal will result in an interrupted cam signal and may set this DTC.
- The following conditions may cause this DTC to set:
- High resistance in the #1 secondary ignition system
- Low resistance in the #4 secondary ignition system
- Corroded or loose #1 or #4 secondary ignition components
- If this DTC is determined to be intermittent, refer to Testing for Intermittent Conditions and Poor Connections. Component Tests and General Diagnostics

TEST DESCRIPTION

Step 1 - Step 9:

Step 10 - Step 19:

The numbers below refer to the step numbers on the diagnostic table.
4. If CYL #1 and/or CYL #4 Misfire Counters are incrementing, there is a condition within the secondary ignition system that effects the camshaft position signal circuit.
6. The ECM supplies 5 volts on the camshaft position signal circuit. This step determines if the ECM is supplying the correct voltage on the circuit.