The electronic ignition control module (ICM) sends a reference signal to the Powertrain Control Module (PCM) seven times per crankshaft revolution (7X reference) in order to indicate the crankshaft position and the RPM so that the PCM can determine when to pulse the ignition coils and control the ignition timing. The ICM applies 5 volts through the 7X reference circuit to the PCM. The PCM switches this circuit to ground for a very short period of time. The seventh pulse is the sync pulse and is used for crankshaft position reference.
• | The engine is running. |
• | A DTC P0341 is not set. |
The CKP resync counter exceeds 15 within 4 minutes and 15 seconds.
• | The malfunction indicator lamp (MIL) illuminates. |
• | The PCM records the operating conditions at the time when the diagnostic fails. This information stores in the Freeze Frame and Failure Records buffers. |
• | A history DTC stores. |
• | The coolant fan turns on. |
• | The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs without a fault. |
• | A history DTC will clear after 40 consecutive warm up cycles without a fault. |
• | Use a scan tool to clear the DTCs. |
• | If the complaint is Cranks But Will Not Run, DTC P0336 may set when attempting to start the engine more than 15 times without turning off the ignition between attempts. |
• | An intermittent problem may be caused by the following items: |
- | The reluctor wheel. Remove the crankshaft sensor and inspect the reluctor wheel through the hole. Inspect for the porosity and the condition of the wheel. Refer to Crankshaft Balancer Cleaning and Inspection . |
- | The crankshaft position (CKP) sensor. Substitute a known good part. Operate the vehicle within the Failure Records and the Conditions for Running the DTC as specified in the supporting text. If the condition still exists, remove the substitute part. |
- | The ignition control module (ICM). Substitute a known good part. Operate the vehicle within the Failure Records and the Conditions for Running the DTC as specified in the supporting text. If the condition still exists, remove substitute part. |
- | The PCM. Substitute a known good part. Operate the vehicle within the Failure Records and the Conditions for Running the DTC as specified in the supporting text. If the condition still exists, remove the substitute part. |
The numbers below refer to step numbers on the diagnostic table.
This step determines if the PCM recognizes a problem. If the DTC does not reset at this point, the problem may be intermittent.
When a Medium Resolution Resync occurs, engine stumble should also occur. If a component's connection or a wire is malfunctioning, an engine stumble or a medium resolution resync may be induced by wiggling the circuit or the connector.
Operating malfunctioning non-engine related electronic components may emit electromagnetic interference (EMI) which may cause a resync. This step will determine if the medium resolution resyncs are being caused by an outside source.
Step | Action | Values | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |||||||
2 | Attempt to start the engine. Does the engine start? | -- | Go to Step 3 | |||||||
Does the DTC reset? | -- | Go to Step 4 | Go to Step 5 | |||||||
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.
Does the engine stumble? | -- | Go to Step 6 | Go to Diagnostic Aids | |||||||
Does the Med. Resolution Resync Counter increment while operating any non-engine related electronic components? | -- | Go to Step 7 | Go to Diagnostic Aids | |||||||
6 |
Did you find and correct the condition? | -- | Go to Step 8 | -- | ||||||
7 |
Did you complete the repair? | -- | Go to Step 8 | -- | ||||||
8 |
Does the DTC reset? | -- | Go to Step 3 | System OK |