Checking secondary air inlet valve -N112 — AUDI

AKL APF
Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1527 B
V.A.G 1594 A
V.A.G 1598/31
VAS 5051 with VAS 5051/1

Test sequence

Note:

The secondary air inlet valve -N112 and the wiring connections are monitored by the engine control unit.

Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 - Engine electronics". For this purpose, the ignition must be switched on.

=> Simos Fuel Injection and Ignition System; Repair group 01
Simos Fuel Injection and Ignition System

Read out the fault memory of the engine control unit.

=> Simos Fuel Injection and Ignition System; Repair group 01
Simos Fuel Injection and Ignition System

If a fault relating to secondary air inlet valve -N112 is displayed:

Unclip secondary air inlet valve -N112 -arrow- from bracket.
Detach hoses from secondary air inlet valve; leave the electrical connector attached.

Connect auxiliary hose to the valve connector marked with an arrow.

Vehicle diagnostic, testing and information system VAS 5051 connected, vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected. For this purpose, the ignition must be switched on.

Display on VAS 5051:

Under -1- select the diagnostic function "03 - Final control diagnosis".

Actuate the secondary air inlet valve -N112:

The valve should click...
...and should open and close (check by blowing into the auxiliary hose).

Exit function "03 - Final control diagnosis" by pressing the ◂ key.
Switch ignition off.

If valve does not open or close properly:

Replace secondary air inlet valve -N112 => Page 26-76.

If the valve does not click during final control diagnosis:

Checking internal resistance

Unplug the connector at the secondary air inlet valve -N112 -arrow-.

Connect multimeter between contacts 1 and 2 on valve to measure resistance.
Specification: 52.5...62.5 ωat room temperature

If specified value is not attained:

Replace secondary air inlet valve -N112 => Page 26-76.

If specification is attained:

Checking power supply

Test requirements:

Fuse for secondary air inlet valve OK.

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations

Fuel pump relay OK.

Note:

The secondary air inlet valve -N112 receives its power supply via the fuel pump relay.

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

Connector / Contact · Measure to
1 · Engine earth

Operate starter briefly.
The LED should illuminate.

Switch ignition off.

If the LED does not illuminate:

Check the wiring from contact 1 on the connector via the fuse to the fuel pump relay for an open circuit using the current flow diagram.
Eliminate open circuit using the current flow diagram.

If the LED illuminates:

Checking actuation

Connect voltage tester V.A.G 1527 B to contacts 1 (positive) and 2 of the connector.

Display on VAS 5051:

Vehicle diagnostic, testing and information system VAS 5051 connected, vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected. For this purpose, the ignition must be switched on.

Under -1- select the diagnostic function "03 - Final control diagnosis".
Actuate the secondary air inlet valve -N112:
The LED must flash slowly.

If the LED lamp does not flash or if it illuminates continuously:

Connect the V.A.G 1598/31 test box to wiring harness connectors; the engine control unit should not be connected. Attach the earth clip of test box to earth -arrow-.

=> Simos Fuel Injection and Ignition System; Repair group 24
Simos Fuel Injection and Ignition System

Important
To prevent damage to the electronic components, select appropriate measuring range before connecting the measuring cables and observe the test requirements.

Check for open circuit and short to positive or earth in the following wiring connection:

Connector / Contact · Test box V.A.G 1598/31 / Socket
2 · 71

Use current flow diagram to eliminate open circuit in wiring/short circuit.

If the wiring is OK:

Replace engine control unit.