Circuit Description
The powertrain control module (PCM) supplies a 12-volt reference circuit and a low reference circuit to both the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor. The CKP sensor sends a signal to the PCM with each revolution of the crankshaft. The CMP sensor sends a signal to the PCM with each revolution of the camshaft. This diagnostic trouble code (DTC) monitors the CKP signal and the CMP signal to determine if they are synchronized. If both signals are not observed by the PCM within a narrow period of time, the PCM will determine that an error has occurred and DTC P0016 will set.
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 - 1 tooth off in either advance or 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 .
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | ||||
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 | -- |
4 | Perform the Camshaft Retard Offset test procedure as follows:
Important: The camshaft retard reading will not be accurate below 1,000 RPM. Is the camshaft retard reading within the specified range? | -20 to +20 degrees | Go to Step 5 | Go to Step 6 |
5 |
Does the camshaft retard reading change more than the specified value? | 2 degrees | Go to Step 6 | Go to Diagnostic Aids |
6 | 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 8 | Go to Step 7 |
7 | Check for proper installation of the distributor. Repair as necessary. Refer to Distributor Inspection . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
8 | Replace the distributor. Refer to Distributor Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 10 |
10 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
