Volkswagen Workshop Service and Repair Manuals

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

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ Diode test lamp V.A.G 1527
• ◆ Fault reader V.A.G 1551 (or vehicle system tester V.A.G 1552) with cable V.A.G 1551/3
• ◆ Adapter set V.A.G 1594
• ◆ Test box V.A.G 1598/31
• ◆ Current flow diagram

Check conditions

• ● → Fuses 30, 31 and 36 must be OK.
• ● The battery voltage must be at least 11.5 V.
• ● All electrical consumers, e.g. lights and rear window heating must be switched off.
• ● If the vehicle is equipped with an air conditioning system, this must be switched off.

Notes:

• ◆ All functions of V.A.G 1551/1552 can also be carried out with the new tester VAS 5051. Connecting VAS 5051 .
• ◆ The final control diagnosis can only be carried out if the engine is stationary and ignition switched on.
• ◆ The final control diagnosis will be broken off if the engine is started or a rotational impulse is recognised.
• ◆ During the final control diagnosis the individual final controls are activated 50 times unless the ⇒ key is pressed to switch manually to the next final control.
• ◆ The final control is checked acoustically or by touch.
• ◆ If it is necessary to repeat the final control diagnosis, without first running the engine briefly, switch the ignition off for approx. 2 seconds.
• ◆ The electric fuel pump will run during the complete final control diagnosis.

Work sequence

• ‒ Connect the fault reader V.A.G 1551 (V.A.G 1552). Then switch ignition on and select engine control unit with the "Address word" 01.
  (Connecting fault reader and selecting engine control unit => Page 01-10 .)

• ‒ Operate fault reader taking into account the information on the display:
• ‒ Press keys 0 and 3 for the function "Final control diagnosis".

Activating fuel pump relay (J17):

• ‒ Confirm input with Q key.

• The fuel pump relay (relay position 1 on relay plate) must click (max. 50 seconds) until the next control element is activated by pressing the ⇒key.

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

Activating activated charcoal filter solenoid valve 1 (N80):

• ‒ Press ⇒key.

• The activated charcoal filter solenoid valve 1 must click (max. 50 seconds) until the next control element is activated by pressing ⇒key.

If the solenoid valve does not click:

• ‒ → Pull the 2 pin connector off solenoid valve 1 (N80) -arrow-.

• ‒ → Connect diode test lamp V.A.G 1527 using adapter cables from V.A.G 1594 to detached connector.
       The LED must flash

LED flashes:

• ‒ Proceed with final control diagnosis until completed.
• ‒ Switch off ignition.
• ‒ Renew activated charcoal filter solenoid valve 1 (N80):

=> Repair group 20; Activated charcoal filter system; Servicing parts of activated charcoal filter system

• ‒ Interrogate fault memory, if necessary, repair any faults and then erase fault memory => Page 01-20 , interrogating and erasing fault memory.

• ‒ Erase the learnt values and adapt the engine control unit again=> Page 24-128 .

LED does not flash:

• ‒ Proceed with final control diagnosis until completed.
• ‒ Switch off ignition.
• ‒ → Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.

• ‒ → Check wiring for open circuit between test box and 2-pin connector:
       Contact 2 and test box socket 61
       Wire resistance: Max. 1.5 ω
• ‒ Check wiring additionally for short to vehicle earth or battery positive.
       Specification: ∞ω

• ‒ Check wire between 2 pin connector contact 1 and fuel pump relay (J17) for open circuit using current flow diagram.
       Wire resistance: max. 1.5 ω

If no fault is detected in the wiring:

• ‒ Replace engine control unit
  => Page 24-121 .

Activating secondary air inlet valve (N112):

• ‒ Press ⇒key.

• Display is of no consequence.

Activating secondary air pump relay (J299):

• ‒ Press ⇒key.

• Display is of no consequence.

• ‒ Press ⇒key.

• ‒ Press ⇒key.

• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.