Operation CHARM: Car repair manuals for everyone.

ETS OFF Lamp On, RPM Sag on a Hot Soak Restart w/A/C On

File In Section: 6E - Engine Fuel & Emission

Bulletin No.: 67-65-20

Date: April, 1996

Subject:
ETS OFF Indicator Lamp Stays Illuminated and/or a RPM Sag on a Hot Soak Restart with the A/C On, SAE J1978 OBDII Scan Tool May Not Communicate with the PCM (New Flash Prom)

Models:
1996 Buick Skylark
1996 Oldsmobile Achieva
1996 Pontiac Grand Am
with 3100 V6 Engine (VIN M - RPO L82)

Condition

Some owners may comment that the ETS (Enhanced Traction System) off light located on the instrument panel stays illuminated and/or a RPM sag on a hot soak (45 minute) restart with the A/C on. Additionally, some service technicians may comment that their non GM Techline SAE J1978 OBDII scan tool will not communicate with the PCM (Powertrain Control Module) when in "Current", "Freeze Frame", or "Test Parameters and Results" mode.

Cause

For "ETS OFF" indicator lamp staying illuminated, the diagnostic calibration was set up so that if certain DTC (Diagnostic Trouble Codes) were set, the PCM would then disable the ETS. Disabling the ETS would then illuminate the "ETS OFF" indicator lamp. Vehicles which have had RPM sags on hot restarts with the A/C on were caused by engine control algorithm. A software/calibration anomaly prevented the non G.M. Techline scan tools from communicating with the PCM.

Correction

A new flash PROM has been released to address the conditions mentioned above. The calibration will be available from Service Technology Group starting with the # 5 CD release.

Parts Information

Do not attempt to order the calibration number from GMSPO. They are programmed into the vehicles PCM via a Tech line Tool Device.

Calibration
Number Emissions

16238674 Nationwide

16238684 Unleaded Export w/o OBDII

Warranty Information

For vehicles repaired under warranty, use: Labor

Operation Labor Time

J6355 Use published labor operation time.