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Removing and installing exhaust gas recirculation valve N18 with exhaust gas recirculation potentiometer G212 > < Checking signal wire between exhaust gas recirculation potentiometer G212 and engine control unit

A4 Mk1

Checking activation of exhaust gas recirculation valveN18
Checking activation of exhaust gas recirculation valve -N18-
Test condition:
l  Voltage supply OK.
   
–  Connect voltage tester -V.A.G 1527 B- to contacts -1- and -5- of the connector.
–  Connect vehicle diagnostic, testing and information system -VAS 5051- and select vehicle system “01 - Engine electronics” from list. Ignition must be switched on → Simos injection and ignition system (4-cyl.); Rep. Gr.01.
  N01-0258
Display on -VAS 5051-:
–  Under selection menu -1- select the diagnostic function “03 - Final control diagnosis”.
–  Press the button → until the valve for exhaust gas recirculation -N18- is actuated.
l  LED should flash slowly.
  Note!
Voltage testers with a low current draw do not go out completely between activation signals from engine control unit, but continue to glow slightly and become distinctly brighter on activation.
–  Exit function “03 - Final control diagnosis” by pressing the ← key.
–  Press “06 - End output”.
–  Switch off ignition.
  A01-0122
If the LED does not flash:
–  Connect test box -V.A.G 1598/31- to connectors of wiring harness; do not connect engine control unit. Connect earth clamp of test box to earth (not shown in illustration) → Simos injection and ignition system (4-cyl.); Rep. Gr.24.
  Caution
To prevent damage to the electronic components, select appropriate measuring range before connecting the measuring cables and observe the test requirements.
  A24-0137
–  Check for open circuit and short to positive or earth in the following wiring:
  N01-0258
Connector
Contact		Test box -V.A.G 1598/31-
Socket
-5-115

–  Eliminate open circuit in wiring (refer to current flow diagram).
If the wiring is OK:
–  Renew engine control unit.
   

Removing and installing exhaust gas recirculation valve N18 with exhaust gas recirculation potentiometer G212 > < Checking signal wire between exhaust gas recirculation potentiometer G212 and engine control unit