Engine Control System - Revised: Overview

Group: 01 (Fuel + Ign.)
Number: 93-02
Date: April 15, 1993

Subject:
New MPI Engine Control System

Model(s):
90 1993 my.

Supersedes TB 01-92-04 of 12/31/92

This bulletin applies to cars with Engine Control Module (ECM) (J1S2), Part No. 8A0 906 2668. To display the ECM number, see "Engine Control Module Version Displaying"

Vehicles with this ECM will be equipped (as a running change in production) with a new Mass Air Flow sensor (without CO-potentiometer) and new Oxygen sensors.

The new control system can be identified as follows:

^ The new Mass Air Flow (MAF) sensor has a 3-wire harness connector.

^ The old Mass Air Flow sensor has a 4-wire harness connector.

Caution!
Do not install the new ECM into vehicles with the old control system and vice versa

This bulletin highlights the important technical changes.

The new ECM has several additional and expanded functions:

^ Function 01: Engine Control Module version, displaying

^ Function 02: Diagnostic Trouble Code (DTC) chart

^ Function O4: Engine basic adjustment

^ Function 07: ECM coding

^ Function 09: Read individual test values, can still be displayed but does not contain useful information.