Checking EGR valve -N18 — AUDI

AHF ALH ASV
Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1527 B
V.A.G 1594 A
V.A.G 1598/22
(vehicles up to 07.99)
V.A.G 1598/31
(Vehicles as of 08.99)
VAS 5051 with VAS 5051/1

Checking internal resistance

Disconnect the exhaust gas recirculation valve electrical connection -N18 -Item 1-.

Connect multimeter between contacts 1 and 2 to measure resistance.
Specified value: 14 ... 20 ω

If specified value is not attained:

Replace the exhaust gas recirculation valve -N18.

Checking power supply

Connect multimeter between contact 2 and earth to measure voltage.
Switch the ignition on.
Specified value: approx. battery voltage

If specified value is not attained:

Check wiring for open circuit and service if necessary.

Checking actuation

Test requirements:

Vehicle diagnostic, testing and information system VAS 5051 connected, vehicle self-diagnosis and vehicle system "01 - Engine electronics" selected.

Connect voltage tester V.A.G 1527 B between contacts 1 and 2.

Display on VAS 5051:

Under -1- select the diagnostic function "03 - Final control diagnosis".
Actuate the EGR valve -N18.
The LED must flash slowly.

Note:

Voltage testers with a low current consumption continue to glow faintly between actuation from the engine control unit (rather than extinguishing completely) and become much brighter when actuated.

Exit the function "03 - Final control diagnosis" by pressing the ◂ key.
Press "06 - End of output".

If the LED lamp does not react as described:

Checking actuation - Vehicles up to 07.99

Connect the test box V.A.G 1598/22 to wiring harness connectors; the engine control unit must not be connected.

=> Diesel Direct Injection and Glow Plug System (4-cyl TDI) > 07.99; Repair group 23; Wiring and component check using test box V.A.G 1598/22
Diesel Direct Injection and Glow Plug System (4-cyl TDI) > 07.99
Wiring and component check using test box V.A.G 1598/22

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 1598/22 / Socket
2 · 29

Rectify any open/short circuit as necessary.

Checking actuation - Vehicles as of 08.99

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-.

=> TDI Injection and Glow Plug System (4-cyl.) 08.99 >; Repair group 23; Wiring and component check using test box V.A.G 1598/31
TDI Injection and Glow Plug System (4-cyl.) 08.99 >
Wiring and component check using test box V.A.G 1598/31

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 · 61

Rectify any open/short circuit as necessary.