Circuit Description
This diagnostic trouble code (DTC) monitors the crankshaft position (CKP) and the camshaft position (CMP) signals to determine if they are synchronized. If both signals are not observed by the control module within a narrow time window, the powertrain control module (PCM) will determine that an error has occurred.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
When the engine is running, the cam sensor pulse is not detected at the correct relative position to the crankshaft position sensor pulse.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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
Check for the following items:
| • | A loose or missing distributor hold down bolt. |
| • | A loose CMP sensor causing a variance in the sensor signal. |
| • | An incorrectly installed distributor that is 1 tooth off in either the advance or the retard positions. |
| • | A loose distributor rotor on the distributor shaft. |
| • | Excessive free play in the timing chain and gear assembly. |
If an intermittent condition is suspected, refer to Intermittent Conditions .
Test Description
The numbers below refer to the step numbers on the table.
-
This test will determine if this DTC is intermittent.
-
If there is a variance in the camshaft sensor signal the variance will be detected in this step.
-
Unintentional damage to the distributor shaft may result if excessive pressure is used to rotate the distributor.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Does the engine speed fluctuate (up to twice the desired RPM)? | -- | Go to Step 3 | Go to Step 4 |
3 | Replace the crankshaft position sensor. Refer to Crankshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
Perform the Camshaft Retard Offset test procedure as follows:
Important: The camshaft retard reading will not be accurate below 1000 RPM. Is the camshaft retard reading within the second specified value? | 1000 RPM -2° to +2° | Go to Step 5 | Go to Step 6 | |
Does the camshaft retard reading change more than the second specified value? | 2000 RPM 2° | Go to Step 6 | Go to Diagnostic Aids | |
With the engine at operating temperature and the engine OFF, perform the following procedure:
Does the rotor turn on the distributor shaft? | -- | Go to Step 9 | Go to Step 7 | |
7 | Check for proper installation of the distributor. Repair as necessary. Refer to Distributor Replacement . Did you find a problem? | -- | Go to Step 10 | Go to Step 8 |
8 | Replace the distributor. Refer to Distributor 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 | |
