INTER. CHECK ENGINE LIGHT ENGINE COOLANT SENSOR LEAKS

IN THE EVENT OF AN ENGINE COOLANT SENSOR LEAK, COOLANT MAY TRAVEL INSIDE THE YELLOW OR BLACK WIRES TO THE NUMBERED ECM CONNECTOR. THE COOLANT MAY CAUSE CORROSION IN THIS AREA. THE CORROSION APPEARS GREENISH IN COLOR, SOMEWHAT LIKE GREASE. IF CORROSION OCCURS, IT MAY CAUSE IMPROPER OPERATION OF THE COMPUTER COMMAND CONTROL SYSTEM INCLUDING INTERMITTENT FLASHING OF THE "CHECK ENGINE" LIGHT WITHOUT STORING TROUBLE CODES OR THE STORING OF CODE 55. IF THESE SYMPTOMS OCCUR, PROCEED AS FOLLOWS: INSPECT THE COOLANT SENSOR FOR LEAKS, REPLACE AS NECESSARY. COOLANT SENSORS BUILT AFTER DAY BUILT CODE 25580 ARE KNOWN GOOD SENSORS. IF THE COOLANT SENSOR IS REPLACED, ALSO REPLACE ABOUT 6 INCHES OF THE YELLOW AND BLACK WIRES FROM THE ECM CONNECTOR END. REPLACING THESE WIRES AND SOLDERING THE CONNECTION WILL STOP THE COOLANT MOVEMENT BEFORE IT REACHES THE ECM CONNECTOR (SEE ILLUSTRATION). IF CORROSION IS PRESENT AT THE ECM CONNECTOR, REPLACE THE AFFECTED CONNECTOR TERMINAL(S), PART #12004610 (THIS NUMBER IS FOR A PACKAGE OF 10). IF COOLANT HAS REACHED THE ECM, REPLACE THE ECM. ** SEE BULLETIN FOR ILLUSTRATION **

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.