TDC Offset Program Procedure

Top Dead Center (TDC) Offset
This procedure should only be used when a DTC has directed you to or one of the following repairs has been performed:

- The engine has been replaced.
- The front engine cover has been replaced.
- The PCM and the Injection pump have been replaced.

The PCM has the ability to perform a TDC Offset learn when one is not present or has been cleared. This procedure allows the PCM to be updated with the correct TDC offset for the vehicle.

NOTE: The TDC Offset specification is only to be used after the Clear and Learn procedure has been performed.

Clearing and Learning TDC Offset
1. One of the above repairs has been performed. If not, do not continue. Refer to On Vehicle Service for repair that was performed.
2. Install Scan tool.
3. Start engine.
4. Operate vehicle until engine coolant temperature is greater than 77° C (170° F).
5. Clear all DTCs.
6. Turn the Ignition ON, engine OFF, hold the accelerator pedal in the wide open throttle position for a minimum of 45 seconds. In this step the TDC Offset is being cleared from the PCM's memory.
7. Turn the ignition OFF for 30 seconds. In this step, the PCM is being powered down.
8. Turn the Ignition ON, engine OFF.
9. Verify in the scan tool that TDC Offset has been cleared to zero. If not, repeat steps 2 through 7.
10. Start the engine.

- Verify in the scan tool that ECT is greater than 77° C (170° F). If not, operate vehicle until desired ECT is achieved (vehicle can be driven or throttle can be depressed until correct coolant temperature is achieved).
- As soon as ECT is greater than 77° C (170° F) and engine speed is below 1500 RPMs, the PCM automatically learns a new offset.

11. TDC Offset should be between -0.25 and -0.75.
12. It not, turn engine OFF and loosen injection pump flange nuts using J 41089.

NOTE: If the PCM fails to program the TDC Offset, do the following:

- Check all PCM and injection timing stepper motor connections.
- Check Techline terminal/equipment for latest software version.
- Try again to program the PCM. If it fails again replace the PCM. Refer to PCM Replacement Programming.

13. Slightly rotate the injection pump (use tool J 29872 to rotate injection pump) and repeat steps 1 through 8 until correct TDC offset has been achieved (1 mm equals 2°). DTC P1214 will be stored if procedure has not been done or offset is out of range (see DTC P1214 for DTC setting criteria).
14. To achieve a negative a (-) number, rotate pump toward driver side; a positive (+) number, rotate toward passenger side (1 mm equals 2°).