INFO. ON INABILITY TO ESTABLISH SCAN TOOL COMM.. Cadillac Catera 1997

SUBJECT: INFORMATION ON INABILITY TO ESTABLISH SCAN TOOL COMMUNICATION WITH THE TRANSMISSION CONTROL MODULE (TCM)

MODELS: 1997 CADILLAC CATERA WITH HYDRA-MATIC 4L30E TRANSMISSION (ML4) ON VEHICLES BUILT FROM S.O.P. THROUGH W06VR52R090366

SOME TECHNICIANS MAY EXPERIENCE DIFFICULTY IN ESTABLISHING SCAN TOOL COMMUNICATIONS WITH THE TRANSMISSION CONTROL MODULE (TCM). THE SCAN TOOL WILL DISPLAY THE MESSAGE "NO COMMUNICATION WITH VEHICLE, CHECK DIAGNOSTIC LINK CONNECTOR, CHECK IGNITION ON/OFF."

THE TCM SOFTWARE ONLY ALLOWS COMMUNICATION WHEN DIRECTLY ADDRESSING THE TCM. IF COMMUNICATION IS INITIALLY MADE WITH THE ECM, COMMUNICATION WITH THE TCM IS NOT POSSIBLE.

ESTABLISH SCAN TOOL COMMUNICATION WITH THE TCM PRIOR TO COMMUNICATING WITH THE ECM. IF COMMUNICATION IS ESTABLISHED WITH THE ECM INITIALLY, CYCLE THE IGNITION KEY OFF FOR AT LEAST 10 SECONDS, TURN THE IGNITION KEY ON AND DIRECTLY ADDRESS THE TCM.

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GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.