PCM - No Communication With OBD II Scan Tool

File In Section: 6E - Engine Fuel & Emission

Bulletin No.: 67-65-27

Date: August, 1996

Subject:
Non-GM SAE J1978 OBD II Scan Tool Does Not Communicate with the PCM (Flash with New Calibration)

Models:
1996 Buick Century, LeSabre, Park Avenue, Park Avenue Ultra, Regal, Riviera, Skylark
1997 Buick LeSabre
1996 Chevrolet Beretta, Corsica, Lumina, Lumina APV, Monte Carlo
1996 Oldsmobile Achieva, Cutlass Ciera, Cutlass Supreme, Eighty Eight, LSS, Ninety Eight, Silhouette
1996 Pontiac Bonneville, Grand Am, Grand Prix, Trans Sport
with 3.1 L, 3.4L, 3.8L Engines (VINs 1, E, K, M, X - RPOs L67, LA1, L36, L82, LQ1)

Condition

Some non-GM SAE J1978 OBD II Scan Tools may not communicate with the Powertrain Control Module (PCM) when in Current, Freeze Frame, or Test Parameters & Results mode. Other scan tool modes including OBD II DTCs (Diagnostic Trouble Codes) are not affected.

Cause

PCM software/calibration anomaly prevents some non-GM scan tools from communicating with the PCM.

Correction

Flash the PCM with new software/calibration. The new software/calibrations are available beginning with the 1996 CD number 12 from GM Service Technology Group.

Important:
There are three methods for programming a PCM:

1. Direct programming. The vehicle is directly connected via the Data Link Connector (DLC) to the dealer's Techline equipment. (T-20 Plus, T-50 and T-60 only) Vehicle must be present.

2. Remote programming. The new program is downloaded into the dealer's scan tool and then downloaded into the vehicle from the scan tool via the DLC. (Tech 2 required for 1997 Model Year) Vehicle must be present.

3. Off-car programming. A PCM may be programmed while removed from the vehicle by using the Off-board Programming Adapter (OBPA), P/N J 41207-B. This adapter can be connected to either the Techline terminal for direct programming or to the scan tool for remote programming. (Do not use Tech 2 with OBPA at this time.) Not necessary for the vehicle to be present.

Refer to the appropriate Service Manual or Techline Information for more detailed instructions.

Important:
Do not attempt to order the software/calibrations from GMSPO. They are programmed into the vehicle's PCM via a Techline Tool Device.

Parts Information








1996 Model Years





1997 Model Years

Warranty Information





For vehicles repaired under warranty, use the table.