ECM - Idle Re-Learn Procedure
90Chevy35Number: 91-114-6E
Section: 6E
Date: November 1990
Corp Bulletin No.: 016541
Subject: USE OF 1987-91 TECH I ECM CARTRIDGE AND PROCEDURE
Model and Year: 1987-89 CAVALIER, CELEBRITY, CORSICA, BERETTA AND CAMARO WITH 2.8L ENGINE 1990 CELEBRITY WITH 3.1L ENGINE 1990-91 CAVALIER, CORSICA, BERETTA AND CAMARO WITH 3.1L ENGINE
TO: ALL CHEVROLET DEALERS
This bulletin is a revision to the Tech 1 Diagnostic "Scan" Tool 1987 thru 1990 ECM Cartridge.
The 1987-1990 ECM Cartridge will not allow the Idle Learn Procedure to function properly. When performing an Idle Relearn on all 1987-1989 A, J, L with 2.8L engine; 1990-91 F, J, L, W with 3.1L engine; or a 1990 A car with 3.1L engine speed density (PFI) engine, you must use the 1987-1991 Tech 1 ECM Cartridge or the following procedure.
NOTICE: IF THE ECM IS WITHOUT BATTERY POWER FOR ANY REASON, THE IACV POSITION INFORMATION FOR A STABLE SATSIFACTORY ENGINE IDLE IS "LOST" AND IS REPLACED WITH A "DEFAULT" VALUE.
To restore the lost IACV position information due to an absence of battery power, perform the following procedure:
1. Restore the battery power and place air conditioning controls (if equipped) in the "off" position.
2. Firmly apply the parking brake and block the drive wheels. Start the engine, and shift the transaxle to "drive" for automatics or "neutral" for manuals.
3. Allow the engine to run a maximum of 10 minutes or until the engine cooling fan has cycled once, whichever occurs first.
4. Shift transaxle to Park (A/T), Neutral (M/T), turn the ignition key to the "off" position for at least 5 seconds.
5. Repeat Step # 2.
6. Allow engine to run for at least 5 minutes.
This procedure will allow the ECM memory to be updated with the "correct" IACV position and provide a stable idle quality.