K 1500 Suburban 4WD V8-393 6.5L DSL Turbo (1994)
Engine Control Module: Service and Repair
Powertrain Control Module (PCM) Replacement
Powertrain Control Module
PCM And Prom
PROCEDURE
Service of the Powertrain Control Module (PCM) should normally consist of either replacement of the PCM or a Programmable Read Only
Memory (PROM) change. If the diagnostic procedures call for the PCM to be replaced, the PROM and PCM should be checked first to see if they
are the correct parts. If they are, remove the PROM from the faulty PCM and install it in the new service PCM. THE SERVICE PCM WILL NOT
CONTAIN A PROM. DTC 51 indicates the PROM is installed improperly or has malfunctioned. When DTC 51 is obtained, check the PCM
installation for bent pins or pin not fully seated in the socket. If it is installed correctly and DTC 51 is still displayed, replace the PROM.
When replacing the production PCM with a service PCM, a DTC 88 will be stored. It is important to program "TDC Offset" into the service PCM
and to transfer the broadcast code and production PCM number to the service PCM label. Please Do NOT record on PCM cover. This will allow
positive identification of PCM parts throughout the service life of the vehicle. For "TDC OFFSET" procedure, refer to TDC Offset Program
Procedure.
CAUTION: To prevent internal PCM damage, the ignition must be "OFF" when disconnecting or reconnecting power to PCM (for example,
battery cable, PCM pigtail, PCM fuse, jumper cables, etc.). The ignition should be "OFF" for at least 30 seconds before disconnecting power to
the PCM. To prevent possible electrostatic discharge to the PCM or PROM, do NOT touch the component leads, or remove integrated circuit from
carrier.
REMOVE OR DISCONNECT
