Audi Workshop Service and Repair Manuals

Checking secondary air inlet valve -N112-

Special tools and workshop equipment required

t	Hand-held multimeter -V.A.G 1526C-

t	Voltage tester -V.A.G 1527B-

t	Auxiliary measuring set -V.A.G 1594C-

t	Adapter cable, 121-pin -V.A.G 1598/31- (test box)

t	Vehicle diagnostic, testing and information system -VAS 5051B-

Procedure   Note The secondary air inlet valve -N112- and the wiring connections are monitored by the engine control unit. l  Vehicle diagnostic, testing and information system -VAS 5051B- connected. –  Switch on ignition and start engine.

Display on -VAS 5051B-: –  From menu -1-, select “Self diagnosis” system and press → key to activate function.

Display on -VAS 5051B-: –  From menu -1-, select vehicle system “01 - Engine electronics” system and press → key to activate function.

Display on -VAS 5051B-: –  From menu -1-, select diagnostic function “004 - Fault memory contents” and press → key to activate function.

Display on -VAS 5051B-: –  From menu -1-, select diagnostic function “004.01 - Interrogate fault memory” and press → key to activate function. If a fault relating to secondary air inlet valve -N112- is displayed: –  Terminate diagnostic function “004.01 - Interrogate fault memory” by touching ← key. –  Select diagnostic function “022 - End output” and switch off ignition.

–  Disconnect hoses from secondary air inlet valve -N112--item 2-; leave electrical connector attached. t  Fitting location: below intake manifold.   Note For illustration purposes, the installation position is shown from the bottom and with the intake manifold removed.

–  Connect test hose to the hose connection on the solenoid air inlet valve -N112- marked with an -arrow-.

–  Switch on ignition and select vehicle system “01 - Engine electronics” again. Display on -VAS 5051B-: –  From menu -1-, select diagnostic function “005 - Final control diagnosis” and press → key to activate function.

–  Press the → key repeatedly until the following display appears: Display on -VAS 5051B- (example): A -  2nd control element being tested 2 -  Secondary air inlet valve -N112- l  The valve will be activated intermittently for approx. 1 minute (and should click audibly). l  The valve should open and close (check by blowing into the test hose). –  Terminate diagnostic function “005 - Final control diagnosis” by touching ← key. –  Select diagnostic function “022 - End output” and switch off ignition. If the valve is not activated (does not click):

Checking internal resistance –  Unplug electrical connector at secondary air inlet valve -N112--item 2-.

–  Connect hand-held multimeter -V.A.G 1526C- to measure resistance between contacts on secondary air inlet valve -N112-. l  Specification: 27 ... 30 Ω. –  If the specification is not attained, renew secondary air inlet valve -N112-. If the specification is attained: Checking voltage supply l  Fuse for secondary air inlet valve -N112- OK → Current flow diagrams, Electrical fault finding and Fitting locations. l  Fuel pump relay -J17- OK; checking → Rep. Gr.24   Note The secondary air inlet valve -N112- is supplied with power via the fuel pump relay -J17-.

–  Connect voltage tester -V.A.G 1527B- between contact -1- of connector for secondary air inlet valve -N112- and earth “–”. –  Briefly operate starter. l  The LED should light up. –  If LED does not light up, check for open circuit in wiring from contact -1- of connector for secondary air inlet valve -N112- via fuse to fuel pump relay -J17- → Current flow diagrams, Electrical fault finding and Fitting locations. –  If necessary repair wiring connection. If the LED lights up:

Checking activation –  Connect voltage tester -V.A.G 1527B- between contacts -1- and -2- of connector for secondary air inlet valve -N112-.

–  Switch on ignition and select vehicle system “01 - Engine electronics” again. –  Repeat diagnostic function “005 - Final control diagnosis”. –  Press the → key repeatedly until the following display appears: Display on -VAS 5051B- (example): A -  2nd control element being tested 2 -  Secondary air inlet valve -N112- l  The LED should flash.

–  If LED does not flash or lights up continuously, connect adapter cable, 121-pin -V.A.G 1598/31- (test box) to connectors of wiring harness; do not connect engine control unit. Connect earth clip of test box to earth → Rep. Gr.24.

–  Check for open circuit and short to positive or earth in the following wiring for secondary air inlet valve -N112-.

Connector Contact	-V.A.G 1598/31- Socket
-2-	9

–  If necessary repair wiring connection.