Volkswagen Workshop Service and Repair Manuals

The final control diagnosis activates the following components in the stated sequence:

1. Throttle valve positioner (V60)

2. Intake air preheating relay (J81)

3. Activated charcoal filter solenoid valve 1 (N80)

Additionally for engine codes AEA and ADX only:

4. Fuel pump relay (J17)

5. Injector (N181)

Special tools, testers and auxiliary items

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ Test box V.A.G 1598/18
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Diode test lamp V.A.G 1527
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Check conditions

• ● Throttle valve potentiometer (G69) OK.
• ● Fuse 18 and 21 OK.

Work sequence

Note:

If the final control diagnosis is to be repeated without the engine being started in between time, switch ignition off for approx. 20 seconds.

• ‒ Remove air cleaner cover.
• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit (address word 01); carry out selection with ignition switched on.

• ‒ Operate fault reader taking into account the information on the display:
• ‒ Input 03 for "Final control diagnosis" function.

Activate throttle valve positioner (V60):

• ‒ Confirm input with Q button.

• The throttle valve positioner plunger must move in and out until switching to the next final control by pressing the ⇒button.

If the throttle valve positioner does not move:

• ‒ Check activation

Activate intake manifold preheating relay (J81):

• ‒ Press ⇒key.

• The intake air preheating relay (above the relay plate) must click until switching to the next final control by pressing the ⇒button.

If the relay does not click:

• ‒ Check intake air preheating relay:

=> Current flow diagrams, Electrical fault finding and Fitting locations

Activate solenoid valve 1 for activated charcoal filter (N80):

• ‒ Press ⇒ button.

• The solenoid valve (right wheel housing) must click until switching to the next final control by pressing the ⇒key (for engine code AEV the final control diagnosis is completed).

If the solenoid valve does not click:

• ‒ Continue check => Page 01-24 .

Actuate fuel pump relay (J17):

• ‒ Press ⇒key.

• The fuel pump relay (on the relay plate with fuse box, relay position 12) must click until switching to the next final control by pressing the ⇒button.

Note:

During the activation of the fuel pump relay the fuel pump must be heard to run at intervals.

If the relay does not click:

• ‒ Check fuel pump relay:

=> Current flow diagrams, Electrical fault finding and Fitting locations, Fuel supply system

Injector (N181) must activate:

• ‒ Press ⇒key.

• The injector must be activated once. Fuel must also be visible briefly on the throttle valve.

Note:

A repeat of the injector check is only possible if the engine is run in between.

Valve does not open:

• ‒ Check activation => Page 24-59 .
• ‒ Press ⇒ key to end the final control diagnosis.

• ‒ Press ⇒ key again.

Note:

After completion of the final control diagnosis input 06 for "End output" function and confirm with Q.

Continuation of check when the activated charcoal filter solenoid 1 does not click:

• ‒ → Pull connector -1- off valve -2- and connect diode test lamp V.A.G 1527 with aux. cables from V.A.G 1594 to disconnected connector.
       The LED must flash

LED flashes:

• ‒ Proceed with final control diagnosis until completed.
• ‒ Switch off ignition
• ‒ Renew solenoid valve.

LED does not flash:

• ‒ Continue with final control diagnosis to end.
• ‒ Switch off ignition

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Check wire between test box socket 1+2 pin connector contact 1 according to current flow diagram for open circuit.
       Wire resistance: max. 1.5 ω
• ‒ Also check wire for short to battery positive and earth.
       Specification: ∞ω
• ‒ Check wire between 2 pin connector contact 2 and relay plate according to current flow diagram for open circuit.
       Wire resistance: max. 1.5 ω

If no wiring fault is detected:

• ‒ Renew Mono Motronic control unit (J257)
  , item 10 .