Circuit Description
The powertrain control module (PCM) has the ability to determine the amount of offset needed to bring the engine to top dead center (TDC). This is used by the PCM to determine proper injection timing.
Conditions for Running the DTC
The ignition is in the ON position.
Conditions for Setting the DTC
| • | The TDC offset is greater than 2.46 degrees |
| or |
| • | The TDC offset is less than -2.46 degrees. |
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
The PCM will only run the diagnostic test when a time set procedure has been activated. It is highly unlikely that the vehicle will be brought in with this DTC set. Refer to Fuel Injection Pump Top Dead Center Offset Adjustment .
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||
2 | Are there any other DTCs set? | -- | Go to Step 3 | |||||
3 | Clear all codes and reset injection timing until TDC offset is between specified values. Refer to Fuel Injection Pump Top Dead Center Offset Adjustment . Does the timing measure within specified value? | -0.25 to -0.75 | Go to Step 6 | Go to Step 4 | ||||
4 | Check the crankshaft position (CKP) sensor for the following items:
Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 5 | ||||
5 |
Important: The new injection pump must be timed. Refer to Fuel Injection Pump Timing Adjustment . Replace the Injection Pump. Refer to Fuel Injection Pump Replacement . Did you complete the replacement? | -- | Go to Step 6 | -- | ||||
6 |
Does the DTC run and pass? | -- | Go to Step 7 | Go to Step 2 | ||||
7 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |
