Engine - Drivability/False Trouble Codes
88chevy12Number: 88-180-6E
Section: 6E
Date: March, 1988
Subject: REVISED PROMS: TO ADDRESS
DRIVEABILITY AND ELIMINATE FALSE "SERVICE ENGINE SOON" LIGHTS
Model and Year:
1987 AND EARLY 1988 R/V, C/K AND G MODELS WITH 5.0L (VIN CODE H) AND 5.7L (VIN CODE K) ENGINES AND LIGHT DUTY EMISSIONS (NA1)
TO: ALL CHEVROLET DEALERS
This bulletin cancels and replaced Dealer service Bulletin 88-33 (Section 6E) dated July 1987, to release new PROMS with additional driveability improvements. All copies of 88-33 should be destroyed.
Some 1987-88 R/V, C/K and G models with TBI engines may experience one or more of the following driveability conditions and/or false codes. If these conditions are experienced, they can be repaired by replacing the PROMs.
Driveability Conditions - 5.0L (LO3) TBI Engine
1. Rolling, surging or rough idles.
2. False Code 54 - Fuel pump circuit (low voltage)
3. False Code 43 - ESC fault
4. Tip-In Sags/Hesitations during engine warm-up
Driveability Condition - 5.7L (LO5) TBI Engine
1. Rolling, surging, or rough idles.
NOTICE: IN ADDITION TO THE PROM CHANGE, IT WILL BE NECESSARY TO RESET MINIMUM IDLE SPEED, PER THE PROCEDURES ON PG. 4-22 OF THE DRIVEABILITY AND EMISSIONS BOOK.
A. Automatic (Drive) 425 plus or minus 25 RPM
B. Manual (Neutral) 500 plus or minimum 25 RPM
2. Low speed road load surge.
3. Detonation and weak acceleration during warm-up.
4. Poor cold starting at minus 20 degrees Fahrenheit.
5. False Code 24 - Vss circuit fault when using 4 wheel drive low lock.
6. Tip-In Sags/Hesitation during engine warm-up.
7. Long crank times, hot or cold.
To repair the above conditions install PROMs per the
following chart.
Use applicable Labor time and Operation number.
L03 (5.0L) TBI ENGINE
L05 (5.7L) TBI ENGINE