The UK quattro Network

Audi MB, 1B and MC Engine Idle Settings

The MB and 1B engines are the only Audi turbo engines that use a pulse-width controlled idle stabilisation valve but do not have a lambda probe. For this reason, setting idle is a little complex.

The idle stabilisation controller (doube-width "relay" in the auxiliary relay panel - code "232") receives a number of inputs and attempts to control idle accordingly. For this reason it is important that the idle stabilisation valve is set to operate in the centre of a range that gives it control scope in both directions. Engine idle speed will be raised deliberately in a number of situations:

If the system is working properly, the engine's idle speed should fall noticeably as the vehicle slows to a halt. A curious corollary of this servo system is that an MB can be carefully accelerated to a good speed simply by engaging gear and releasing the clutch gently - the idle stabilisation controller will return the engine to the set idle speed - the process can be repeated into third or even fourth gear.

Tools required:


Kerbside Motors Home Page and Contact Information