VW Passat & Audi A4 1990-2000

General Information


Diagnostic Trouble Codes, also called DTCs, are used to provide the technician with a digital representation of a fault which has been detected by the ECM. When such faults are detected, they are stored in the ECM and can be retrieved and used to help diagnose the faulty area and determine if a wiring circuit, connectors, or component has failed.

DTCs are retrieved and cleared with the use of a proper scan tool. These actions are described in their respective sections below.