EXPERTEC TSB (91-T-156)

Publication date: 1991-05-29
Reference number: 91-T-156

EXPERTEC TSB

TECHNICAL SERVICE BULLETIN

Reference Number(s): 91-T-156, Date of Issue: 05/29/91

INTERRUPT. OF PCM/BCM WHEN - DIAG. TOOL IS CONNECTED

Model(s): 1991 Oldsmobile Toronado, Trofeo

Bulletin No.: 91-T-156

Date: 05/29/1991

SUBJECT

Interruption Of PCM-BCM Communication When A Diagnostic Tool Is Connected To The ALDL - Install A Revised MEMCAL

SERVICE INFORMATION

Some 1991 Toronado and Trofeo models equipped with 3800 T.P.I. (VIN L) engine, built prior to vehicle number MU306201, (Federal calibration) or MU306180, (California calibration) may have a condition that prevents the PCM from communicating with the BCM when a diagnostic tool is connected to the vehicle's serial data (ALDL) connector. This condition only occurs when a diagnostic tool is connected to the vehicle's ALDL connector.

Should this condition exist on a vehicle, technicians may observe specific functions that are affected.

A/C clutch remains on or off.
BCM Code 334 (BCM-PCM communication error) is stored.
Coolant temperature gauge and tachometer are not displayed.

This condition may lead to improper diagnosis and unnecessary repairs. It is recommended that a new revised calibration mem-cal be installed.

PARTS INFORMATION

The mem-cals are currently available through GMSPO under the following part numbers.

PARTS INFORMATION

Axle Ratio	Scanner I.D.	Broadcast Code	Service Part #
3.06 3.06	Fed. 1464 Calif. 1474	AXMU AXMW	16162582 16162586