PCM - OBD Software Upgrade

File In Section: 6E Engine Fuel & Emission

Bulletin No.: 87-65-09

Date: March, 1998

OBD SOFTWARE UPGRADE

Subject:
On Board Diagnostic (OBD) System Improvements
(Reflash Calibration)

Models:
1997 Chevrolet Lumina, Monte Carlo
with 3100 V6 Engine (VIN M - RPO L82) with Automatic Transmission

VIN Breakpoints:
Start of Production (SOP) to End of Production (EOP)

While the subject vehicle has 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 whenever practical.

Condition

1997 Chevrolet Lumina and Monte Carlo 3.1L V6 engine equipped vehicles misfire diagnostics have been inadvertently disabled when the fuel system's fuel level sensor fails in the empty position.

Cause

The vehicles were released with software which inadvertently disabled the misfire diagnostics when the fuel system's fuel level sensor fails in the empty position.

Correction

Use a Tech II to verify what software is programmed into the vehicle's Powertrain Control Module (PCM). If the improved software has not been installed, reprogram/reflash with the updated software. Refer to the calibration table for the appropriate calibration change.

Calibration Information

The calibrations listed are FLASH calibrations and NOT available from GMSPO. Service FLASH calibrations are available starting with the 1998 CD # 3.

Model Emission Type Calibration

W USA Nationwide 09355514
W Canadian/Unleaded fuel 09355524
export
USA Nationwide 09355544
Canadian Unleaded fuel 09355554

Important:
Inform customers that this work is being performed on their vehicles to improve On Board Diagnostic system operation and does not affect vehicle durability, reliability, or performance.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation Labor Time
J-6355 Use published labor
operation time

Important:
This labor operation is covered under either the Federal or California Emission Control System Warranty (whichever applies) or the "Bumper to Bumper" coverage in the New Vehicle Limited Warranty. The warranty with the broadest coverage applies.