3.1/3.4L Eng False DTC P0121 - Reprogram Pcm (77-65-14A)

Publication date: 1998-05-01
Reference number: 77-65-14A
Supersedes refnos: 77-65-14

3.1/3.4L ENG FALSE DTC P0121 - REPROGRAM PCM

TECHNICAL SERVICE BULLETIN

Reference Number(s): 77-65-14, 77-65-14A

FALSE DTC P0121 (REPROGRAM PCM)

Model(s): 1997 Buick Century, Skylark

1997 Chevrolet Lumina Monte Carlo Malibu, Venture

1997 Oldsmobile Achieva, Cutlass, Cutlass Supreme,

Silhouette

1997 Pontiac Grand Am, Grand Prix, Trans Sport

with 3100/3400 V6 Engine (VlNs M, E

- RPOs L82, LA1) Section: 6E - Engine Fuel & Emission Bulletin No.: 77-65-14A Date: May, 1998

NOTE: This bulletin is being revised to add additional models and calibration numbers. Please discard Corporate Bulletin 77-65-14 (Section 6E - Engine Fuel & Emission).

CONDITION

Some owners may experience a MIL (Malfunction Indicator Lamp) light illuminated on the vehicle's instrument panel. Additionally, the engine's normal controlled idle speed may be slightly elevated when the MIL is illuminated.

CAUSE

The current DTC (Diagnostic Trouble Code) P0121 is too sensitive. The rational check that the diagnostic calibration performs has been changed. Part of those changes involve eliminating the defaulted higher idle.

CORRECTION

Check the calibration identification number utilizing a scan tool device. Re-flash with the updated calibration if the current calibration is not one listed in this bulletin. If the vehicle already has the most recent calibration, then refer to the appropriate service repair manual to diagnose and repair for DTC P0121. Test drive the vehicle after repair to ensure that the condition has been corrected. The new calibrations are available from the GM Service Technology Group starting with CD number 6 for 1998.

NOTE: Do not attempt to order the calibrations from GMSPO. The calibrations are programmed into the vehicles PCM via a Techline Tool device.

CALIBRATION INFORMATION

Calibration Number	Carline	Emissions
16254334	Achieva, Grand Am, Skylark	Nationwide
16254384	Century	Unleaded Export
16254394	Century	Nationwide
16258174	Cutlass, Malibu	Unleaded Export
16258184	Cutlass, Malibu	Leaded Export
16258164	Cutlass, Malibu	Nationwide
09359774	Venture, Silhouette, Trans Sport	Federal
09359784	Venture, Silhouette, Trans Sport	California
09359794	Venture, Silhouette, Trans Sport	Unleaded Export
09359804	Trans Sport	Unleaded Export High Speed with XNA Tires
09355514	Lumina, Monte Carlo	Nationwide
09355524	Lumina, Monte Carlo	Canadian Unleaded Export
09355544	Lumina, Monte Carlo	USA Nationwide Police/Taxi
09355554	Lumina, Monte Carlo	Canadian Unleaded Export Police/Taxi
09359554	Grand Prix	USA Nationwide
09359564	Grand Prix	Unleaded Export
09359594	Cutlass Supreme	USA Nationwide
09359604	Cutlass Supreme	Unleaded Export

WARRANTY INFORMATION

For vehicles repaired under warranty, use:

WARRANTY INFORMATION

Labor Op	Description	Labor Time
J6355	On-Car Prom Reprogramming Flash E Prom	Use Published Labor Operation