Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

1994 Audi S4FACTORY OEM SERVICE PROCEDURE

Checking Coding Connector Wiring

The following test should only be performed if code 4 is NOT displayed when the engine control module version is called up.

Connect test box (VAG 1598) to the Motronic ECM harness connector using adaptor cable (VAG 1598/5).

NOTE: Motronic ECM is left disconnected.

Check the following wires, see CODING CONNECTOR INTERFACE TERMINALS table for short circuit to positive or short circuit to ground using the proper wiring diagram, and repair or replace as necessary. See WIRING DIAGRAMS .

CODING CONNECTOR INTERFACE TERMINALS

Terminal On Coding Connector

⁽¹⁾ VAG 1598 socket

⁽¹⁾ Motronic ECM connector terminal

⁽¹⁾	Terminal numbering for the Motronic ECM -J220- harness connector is the same as the VAG 1598 test box. See Figure .

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.