Test requirements:

WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Fuses for engine electronics OK
See appropriate System Wiring Diagram article.
Ground (GND) connections at engine and transmission OK
Battery voltage at least 12.5 V
Exhaust system free of leaks.
Vehicles with automatic transmission: Selector lever in position "P" or "N".
Electrical consumers switched off (radiator fan must NOT run during test).
A/C switched off.
No DTCs in DTC memory; check DTC memory. See MODE 3: CHECK DTC MEMORY .
Throttle valve angle 12.0 to 16.0%. See "PID 17: Throttle valve position (absolute)", MODE 1: CHECK MEASURED VALUES .

Let vehicle cool off with the ignition switched off until the following conditions are met:

Intake air temperature 10 to 50 °C. See "PID 15: Intake air temperature"; MODE 1: CHECK MEASURED VALUES .
Coolant temperature approximately Intake Air Temperature (10 to 50 °C). See "PID 05: Coolant temperature"; MODE 1: CHECK MEASURED VALUES .