For 1990-2009 cars

# COMPUTER COMMAND CONTROL FALSE SETTING OF CODE 24

A CHECK ENGINE LIGHT MAY BE TURNED ON AND A CODE 24 STORED WHEN THE THROTTLE IS OPENED AND THE ROAD SPEED SENSOR CONTINUES TO READ ZERO (0) FOR FIVE (5) SECONDS.

THIS CAN OCCUR UNDER CONDITIONS SUCH AS TRYING TO GET MOVING UP A STEEP INCLINE, DRIVING THE VEHICLE IN REVERSE OR WHEN AN ENGINE IS LOADED TO STALL SPEED AGAINST THE BRAKES.

AS AN INTERIM 1982 PRODUCTION FIX, A NEW ECM WAS RELEASED WITH A NEW RPOM THAT EXPANDED THE CODE 24 TIMER FROM FIVE (5) TO SIXTY (60) SECONDS.

THE EARLY ECM PROM, AND AFTER JOB PROM ARE NOT INTERCHANGEABLE.

THE FOLLOWING PART NUMBERS ARE TO BE USED TOGETHER AND NOT INTERMIXED:

START OF PRODUCTION

BROADCAST ECM OEM ECM SERVICE PROM CODE PART NO. PART NO. PART NO. APPLICATION

AAN 16020181 1225500 1225490 2.8L, 125 AUTO WITH/OUT TCC SKYLARK

RS 16016931 1225500 1225519 2.8L, 125C AUTO WITH TCC SKYLARK

RY 16016961 1225500 1225527 2.8L HIGH/OUTPUT, 125C AUTO WITH TCC

ATC 16025701 N/A N/A 2.8L 125 AUTO WITH/OUT TCC

ATB 16025701 1225950 1226012 2.8L, 125C AUTO WITH TCC

ATJ 16025761 1225950 1226015 2.8L, HIGH/OUTPUT 125C AUTO WITH TCC

THE MIDYEAR CHANGE INCORPORATES THE CODE 24 EXPANDED TIMER CHANGE TO SIXTY (60) SECONDS.

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.