ECM Locks Up During Programming - DO NOT INSTALL A NEW ECM - keywords calibration code communuication data engine error line module no PCM performance repeat serial TCSC tech2 techline TIS2000 up

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

A communication error message may be displayed during ECM programming and unsuccessful ECM programming may be encountered. As a result, the ECM may lock up and no ECM communication will be present.

If an ECM locks up during programming, do not replace the ECM. Instead, use the following procedure to unlock and program the ECM:

1. Turn the problem vehicle's ignition OFF and remove the locked up ECM.
2. Connect a known good 2005 Saturn ION to the Saturn Service Stall and begin programming procedure.

Important: Select the "Replace and Reprogram" option on the first screen of "Service Programming System". Additionally, if the following procedure does not unlock the ECM, follow it again but select the "Reprogram" option instead of the "Replace and Reprogram" option.

3. Continue until the Saturn Service Stall displays the VIN screen.
4. Turn the known good vehicle's ignition OFF, remove the known good ECM, and install the locked up ECM in its place.
5. At the Saturn Service Stall, delete the VIN that is on the screen and type in the problem vehicle's VIN.
6. Turn the known good vehicle's ignition ON and continue programming the locked up ECM by selecting the problem vehicle's options and calibration.
7. If error messages are encountered, continue selecting "OK" to proceed with ECM programming.
8. After ECM programming is complete, turn the known good vehicle's ignition off for at least 30 seconds.
9. Remove the previously locked up ECM and install both ECMs back into their original locations.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.