Powertrain Controls - ECM/PCM

***THIS ARTICLE REFLECTS CHANGES MADE BY TECHNICAL SERVICE BULLETIN # 477130, DATED AUGUST, 1994***

ENGINE CALIBRATIONS
Powertrain Control Module (PCM) calibrations are stored in the Electronically Erasable Programmable Read Only Memory (EEPROM). The EEPROM is not removable from the PCM.

DIAGNOSTIC TROUBLE CODE 51 WILL SET
Diagnostic Trouble Code (DTC) 51 will set if no calibration was programmed in the PCM, or when the PCM detects an internal program fault (Checksum Error). If DTC 51 sets during normal vehicle operation, replace the PCM. The replacement PCM must be programmed using Tech 1 scan tool (T1) or CAMS (T100).

ZEROING ADAPTIVE CELLS
Failure to clear the adaptive cells could result in a Checksum Error. To properly clear the adaptive cells, use a scan tool while following these steps:
1. Zero the adaptive cells.
2. Key off for 15 seconds.
3. Key on.

PCM REPROGRAMING PROCEDURE

CAUTION: The software/calibration used for PCM reprogramming must match the vehicle application, or improper operation and/or vehicle damage may occur.

^ Battery is charged.
^ Ignition is "ON."
^ Connections to the Data Link Connector (DLC) and battery/cigarette lighter secure.
^ Follow the most current Techline terminal/equipment instructions.

PCM FAILS TO PROGRAM OR DTC 51 SETS DURING PROGRAMMING
^ Check all PCM connections.
^ Check Techline terminal/equipment for latest software version.
^ Repeat reprogramming procedure. If it fails again, replace the PCM. The replacement PCM must be programmed.

AFTER REPAIRS
Confirm "CLOSED LOOP" operation and no Malfunction Indicator Lamp (MIL) (Service Engine Soon).