Audi Workshop Service and Repair Manuals > A3 Mk1 > Power unit | Simos injection and ignition system (4-cylinder) | Mixture preparation system, electronic inj.,Gas | Checking Lambda control | Checking lambda probe and lambda control downstream of catalytic converter

Checking basic voltage

–	Unscrew protective cover -arrows- on vehicle floor.

–	Unplug 4-pin connector -1- (brown) for lambda probe downstream of catalytic converter -G130-.

–	Connect the multimeter for voltage measurement range (direct voltage) between contact 3 and contact 4.

–	Switch on ignition.

t	Specification: 0.400 ... 0.500 V

–	Switch off ignition.

If specification is not attained:

–	Check lambda probe wiring → Chapter

If specification is attained:

–	Replace lambda probe downstream of catalytic converter -G130.