1994 Audi S4FACTORY OEM SERVICE PROCEDURE

Checking ECM Version

NOTE: Following procedure is for checking ECM version using manufacturer scan tool (VAG 1551).
  1. Check DTC memory. See RETRIEVING DIAGNOSTIC TROUBLE CODES  .
  2. Display will read - "RAPID DATA TRANSFER" "SELECT FUNCTION XX".
  3. Press buttons -0- and -1- to select "CHECK CONTROL MODULE VERSIONS" function 01.
  4. Display will read - "RAPID DATA TRANSFER" "01-CHECK CONTROL MODULE VERSION".
  5. Press -Q- button to confirm input.
  6. Display will read - "4A0907551AA 2.21 R5 MOTR RHV HS D" "CODING 4".
  7. This display can be broken down as follows, see MOTRONIC ENGINE CONTROL MODULE VERSION  table.
CHECKING ECM VERSION

Applications Scan Tool Display
ECM Identification (1) 4A0907551AA
Engine Displacement 2.21 Liter
Engine Type: R In-Line 5 Cylinder
Fuel Injection Type: MOTR Motronic Multiport Fuel Injection
Ignition Type: RHV Resting High Voltage Distribution
Transmission Type: HS Manual
Transmission Type: AT Automatic
ECM Software: "D" Manufacturers Use Only
Coding (Number) (2) 1 or 4
(1) Check with parts for updated versions.
(2) For 1 or 4 coding definitions. See ECM CODING  .
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.