Century V6-3100 3.1L VIN M SFI (1998)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
Engine Controls - OBD System Improvement/Correction
File In Section: 06 - Engine/Propulsion System
Bulletin No.: 99-06-04-037
Date: September, 1999
TECHNICAL
Subject:
On-Board Diagnostic (OBD) System Improvements (Reprogram PCM)
Models:
1998 Buick Century, LeSabre, Park Avenue, Regal, Skylark
1998 Chevrolet Camaro, Lumina, Malibu, Monte Carlo, Venture
1998 Oldsmobile Achieva, Cutlass, Eighty-Eight, Intrigue, Silhouette
1998 Pontiac Bonneville, Firebird, Grand Am, Grand Prix, Trans Sport
1998 Chevrolet and GMC C/K Pickup, G, M/L, P, S/T Trucks
1998 Oldsmobile Bravada
with 3.1 L, 3.4 L, 3.8 L, 4.3 L, 5.0 L or 5.7 L Engine
(VINs M, E, K, 1, W, X, M, R - RPOs L82, LA1, L36, L67, L35, LF6, L30, L31)
Although the subject vehicles equipped with the listed engines have been certified as complying with the applicable U.S. Environmental Protection
Agency (EPA) and California Air Resources Board (CARB) On-Board Diagnostic (OBD) requirements, we have identified an OBD system
improvement that should be implemented as necessary.
Condition
1.
When using a generic scan tool (non-Tech II), catalyst monitoring test results will not be available once the engine is shut off.
2.
Erroneous idle catalyst monitor test values will be reported to the technician if using a generic scan tool (non-Tech II).
Cause
1.
Catalyst monitoring test results are stored in volatile RAM and are only available from the completion of the test until key-off.
2.
Due to a software anomaly, erroneous idle catalyst monitor test values and limits will be reported which can confuse a service technician.
Correction
1.
Record catalyst monitoring test results prior to turning the engine off when using a generic scan tool (non-Tech II).
2.
When using a generic scan tool, recalibrate the vehicle with the latest calibration available for the vehicle application, if test data are required for
vehicle diagnosis. Recalibration will correct the software anomaly which reports the incorrect data.
Calibration Information
The calibrations are programmed into the vehicle's PCM via a Techline tool. Calibrations are available from General Motors on the TIS 2000 Disc # 17
CD ROM.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Labor Description
Labor Time
J6355
Prom - Reprogramming
Use Published
on vehicle
Labor Time
