Engine Control Module Coding

Code Engine Control Module

The factory performs ECM Coding in the wiring harness at connectors B and C of the ECM .

The first three digits are coded via terminals 14, 16 and 19 of connector B and the fourth digit via terminal 9 of connector C.

If one of these terminals is connected to ground a zero is displayed; if the terminal is open, a 1 is displayed in the appropriate position of the code

During ECM identification, a four-digit code must always be displayed on the scan tool.

If the appropriate coding for the vehicle is not displayed on VAG 1551:
- Check ECM terminal assignment using wiring diagram.

If incorrect ECM terminal assignments determined:

- Correctly install terminals in connectors B and C.

If ECM terminal assignments are correct:

- Replace the ECM.

After coding is corrected:

- Road test

^ Driveability OK

^ Malfunction Indicator Lamp (MIL) does not come on

- Re-check DTC memory to be sure no malfunctions stored.

Incorrect ECM coding leads to:

^ Driveability problems (jerky shifting, jolts during load changes, etc.)

^ Increased fuel consumption

^ Exhaust emission out of specification

^ Decrease in transmission life

^ Storage in DTC memory of malfunctions that do not exist

^ Some functions may become inoperative (oxygen sensor control, EVAP canister purge regulator valve, etc.)