Engine Control Module: Application and ID

ENGINE CONTROL MODULE (ECM) VERSIONS - OVERVIEW:

Engine Control Modules:
4A0 906 266 A
4A0 906 266 AA
4A0 906 266 AB

These are the introductory version and successor versions for the USA Audi 100 with On Board Diagnostic (OBD I). The engine control modules are downwardly compatible.

Engine Control Module:
8A0 906 266 B

With this version, the MFI ECM was completely modified. Important new features are:
- Oxygen sensor control with learning function; CO adjustment on Mass Air Flow (MAF) sensor eliminated.
- Coding of MFI ECM using VAG 1551 scan tool and "Code Control Module" function 07.

Engine Control Modules:
8A0 906 266 E
8A0 906 266 H
8A0 906 266 J

These are the successor versions of the 8A0 906 266 B control module.

Engine Control Module:
8A0 906266 D

With this version, the On Board Diagnostic II (OBD II) was used in the Audi A6 with 2.8 liter V6, manual transmission and front wheel drive. Important new features on vehicles with OBD II are:
- Additional Heated Oxygen Sensor (HO2S) probe after Three Way Catalytic Converter (TWC).
- New engine control module with five individual connectors, total of 96 terminals.
- New On Board Diagnostic (OBD) program with address word 01 and address word 33.

Engine Control Modules:
8D0 906 266
8D0 906 266A

These are the successor versions of the 8A0 906 266 D control module with On Board Diagnostic II (OBD II).

ON BOARD DIAGNOSTIC (OBD II) TECHNICAL DATA:
Memory:
Permanent memory:
- If the engine control module is disconnected from the permanent battery positive voltage (B+) supply, the Diagnostic Trouble Code (DTC) memory and "Readiness Code" will be erased.

Data Output:
Rapid data transfer.
Additional malfunction display by Malfunction Indicator Light (MIL) lighting up.

Address Words:
Address word 00:
- Automatic Test Sequence (Switch ignition on or let engine idle).
Address word 01:
- Engine Electronics (Switch ignition on or let engine idle).
Address word 33:
- OBD II (Switch ignition on or let engine idle).

Functions Under Address Word 01:
Function 01:
- Check Control Module Versions (Switch ignition on or let engine idle).
Function 02:
- Check DTC Memory (Let engine idle, or, crank engine with starter for at least 5 sec. without switching ignition off).
Function 03:
- Output Diagnostic Test Mode (Switch ignition on).
Function 04:
- Basic Setting (Let engine idle).
Function 07:
- Code Control Module (Switch ignition on).
Function 08:
- Read Measuring Value Block (Switch ignition on or let engine idle, or driving).

Modes Under Address Word 33:
Mode 1:
- Transfer diagnosis data (Switch ignition on or let engine idle).
Mode 2:
- Transfer operating conditions (Switch ignition on or let engine idle).
Mode 3:
- Check DTC memory (Switch ignition on or let engine idle).
Mode 4:
- Erase diagnosis information (Switch ignition on or let engine idle).
Mode 5:
- Output of HO2S signals (Switch ignition on or let engine idle).
Mode 6:
- Read test results; starting with control module 8D0 906 266 A (Switch ignition on or let engine idle).
Mode 7:
- Read test results; starting with control module 8D0 906 266 A (Switch ignition on or let engine idle).

NOTES:
- Under address word 33, Mode 1 to Mode 5 can be selected starting from control module 8D0 906 266 and Mode 1 to Mode 7 starting from control module 8D0 906 266 A.
- Individual measuring values can be read under Mode 1. This is not recommended for Audi service department since this information is available more easily under address word 01, function 04 and/or function 08.
- Mode 2 shows the operating conditions under which a malfunction was recognized.
- Mode 3 is used to check the DTC memory and Mode 4 is used to erase the DTC memory. In the Audi service department, only address word 01, function should be used to erase, since with Mode 4 the DTC memory is erased immediately even if it was not checked first.
- Static variables of HO2S probes, required by legal regulations, are displayed under Mode 5. Since these variables have no direct relationship to HO2S diagnosis, Mode 5 is not needed by the Audi service department.
- Mode 6 is used to read all test results from components and systems that are NOT continuously monitored.
- Mode 7 is used to read test results of components and systems that are continuously monitored.