Audi Workshop Service and Repair Manuals > A4 Mk1 > Power unit | 4-Cylinder engine (2-valve), Mechanics | Exhaust system | Exhaust gas recirculation system - vehicles with engine code letters ANA | Electrical test of exhaust gas recirculation valve N18 and exhaust gas recirculation potentiometer G212 | Checking power supply for exhaust gas recirculation valve N18

Checking power supply for exhaust gas recirculation valveN18

Checking power supply for exhaust gas recirculation valve -N18-

Test condition:

l	Check that current supply relay for Simos control unit -J363- is OK. → Simos injection and ignition system (4-cyl.); Rep. Gr.28

Note!

The power supply to the exhaust gas recirculation valve is provided by the current supply relay for the Simos control unit -J363-.

–	Connect voltage tester -V.A.G 1527 B- as follows:

Connector Contact	Measure against
-1-	Engine earth

–	Switch on ignition.

l	The LED should light up.

–	Switch off ignition.

If the LED does not light up:

–	Refer to current flow diagram to check for open circuit in wiring leading from contact 1 of connector to current supply relay for Simos control unit -J363--item 3- (in 3-position relay carrier in electronics box, plenum chamber, left-side).

–	Eliminate open circuit in wiring (refer to current flow diagram).

If the LED lights up, check voltage supply for exhaust gas recirculation potentiometer -G212-.