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EGR - Disabled BySetting Of DTC P1189

File In Section: 6E - Engine Fuel & Emission

Bulletin No.: 87-65-24

Date: September, 1998

OBD SOFTWARE UPGRADE

Subject:
On-Board Diagnostic (OBD) System Improvements (Re-Flash Calibration)

Models:
1998 Cadillac Concours, DeVille, Eldorado, Seville
1998 Oldsmobile Aurora
with 4.0L, 4.6L Engine (VINs C, Y, 9 - RPOs L47, LD8, L37)

Although the subject vehicles have been certified as complying with the applicable U.S. Environmental Protection Agency (EPA) and California Air Resources Board (CAR B) On-Board Diagnostic (OBD) requirements, we have identified an OBD system improvement that should be implemented whenever practical.

Condition

Engine EGR operation may be inadvertently disabled by the setting of DTC P1189 - Engine Oil Pressure Switch Circuit.

Cause

Vehicles were produced with software which may inadvertently disable EGR operation.

Correction

Use a Tech II scan tool to verify what software calibration is programmed into the vehicle's PCM. If the improved calibration has not been installed, re-flash the PCM with the updated calibration listed in this bulletin.

Calibration Information

The calibrations listed are FLASH calibrations and are NOT available from GMSPO. The calibrations are programmed into the vehicle's PCM via a Techline tool device and are available from General Motors Service Technology Group (STG) starting with 1998 Disc 18.





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 Description Labor Time

J6355 PROM - Reprogramming Use published
On Car 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.