INFORMATION ON UART COMMUNICATION LINK. Buick Riviera 1995

SUBJECT: INFORMATION ON UART (UNIVERSAL ASYNCHRONOUS RECEIVE AND TRANSMIT) COMMUNCIATION LINK WITH SCAN TOOL INSTALLED

MODELS: 1995 BUICK RIVIERA 1994-95 OLDSMOBILE EIGHTY EIGHT AND NINETY EIGHT WITH 3.8L ENGINES (VINS L, 1 - RPOS L27, L67) AND EQUIPPED WITH U2A OR UH8 GAUGE CLUSTER

THE INTENT OF THIS BULLETIN IS TO INFORM TECHNICIANS ABOUT A NORMAL CONDITION THAT EXISTS WHILE USING A SCAN TOOL ON VEHICLES EQUIPPED AS STATED ABOVE. WHEN THE SCAN TOOL IS CONNECTED TO THE VEHICLE, THE UART COMMUNICATION LINK IS DISRUPTED. THE DISRUPTED COMMUNICATION LINK WILL RESULT IN ONE OR MORE OF THE FOLLOWING CONDITIONS:

VOLT INDICATOR LAMP ILLUMINATED

HOT INDICATOR LAMP ILLUMINATED

STOP ENGINE HOT DISPLAYED ON OLDSMOBILE WITH DRIVER INFORMATION CENTER

BRAKE TO SHIFT LAMP ILLUMINATED

PRNDL INDICATOR WILL REMAIN FIXED

USE THE SCAN TOOL DATA TO DETERMINE ACTUAL COOLANT TEMPERATURE, BATTERY VOLTAGE, OR PRNDL POSITION. OUTPUT TESTS OF THE INSTRUMENT PANEL INDICATOR LAMPS USING THE SCAN TOOL WILL NOT BE POSSIBLE.

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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.