DeVille V8-4.6L VIN Y (1998)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
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.
