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 #1 or #3 cylinder has fired on the 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 powertrain control module (PCM) 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 PCM can accurately time the operation of the fuel injectors. If the PCM receives an intermittent CMP signal from the ICM then the CMP Resync Counter on the scan tool will increment. When the PCM cannot use the information from the CMP signal, a DTC will set. DTC P0341 sets when the PCM detects too many CMP Resyncs within a certain amount of time.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The PCM sees more than 30 CMP Resync counts in a 256-second window when manifold absolute pressure (MAP) is more than 30 kPa .
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 DTC P0336 is set, diagnose that DTC first. An intermittent fault in the CKP circuit will cause the PCM to resync the cam and may set this DTC. If the PCM is resyncing the camshaft, the CMP Resync Counter on the Scan tool will increment with the engine running. |
| • | An intermittent short to voltage on circuit 633 can set this DTC. A direct short to voltage on circuit 633 will set P0340, as there will be no change in the cam signal input. |
| • | Electromagnetic interference (EMI) may also set DTC P0341. Inspect the wiring harness for damage. If the harness appears to be OK, observe the CMP resync counter on the scan tool while moving connectors and wiring harnesses related to the CMP sensor. If the CMP resync counter still does not count, while observing the scan tool, operate any non-engine related electrical components on the vehicle. A change in display will indicate the location of the malfunction. |
If this DTC is determined to be intermittent, refer to Intermittent Conditions .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if DTC P0341 is the result of a hard malfunction or an intermittent condition.
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The counter should stop incrementing with the CMP circuit disconnected and set DTC P0340. If the counter still increments, this indicates that the PCM is malfunctioning.
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A faulty electrical connection in the CMP circuit can cause the CMP Resync Counter to increment. Anytime a faulty electrical connection is present, the CMP Reference Activity counter will stop incrementing.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 |
Are any other DTCs set? | Go to Step 3 | |
Is the CMP Resync Counter incrementing? | Go to Step 4 | Go to Diagnostic Aids | |
Did the CMP Resync Counter stop incrementing? | Go to Step 5 | Go to Step 7 | |
Did you find and correct the condition? | Go to Step 9 | Go to Step 6 | |
6 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- |
7 |
Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
8 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC run and pass? | Go to Step 10 | Go to Step 2 |
10 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed. | System OK | |
