Volkswagen Workshop Service and Repair Manuals

Note:

The basic setting matches the Digifant control unit to the throttle valve potentiometer, idling stabilization valve and the engine, at idling speed.

Special tools, testers and auxiliary items

• ◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3
• ◆ Ignition tester V.A.G 1767 or V.A.G 1367 with HT pick-up clamp V.A.G 1367/8

Check conditions

• ● Engine oil temperature min. 80 °C
• ● Electrical consumers switched off (radiator fan must not run during the check)
• ● Air conditioner switched off
• ● Accelerator cable adjustment OK

=> Repair group 20, removing and installing parts of the fuel supply system, adjusting accelerator cable

Test sequence

• ‒ → Pull crankcase breather hose -1- off pressure regulating valve -2- and route so that only fresh air can be drawn in.

• ‒ → Connect ignition tester V.A.G 1367 with pick-up clamp V.A.G 1367/8 or ignition tester V.A.G 1767.
• ‒ Interrogate fault memory, if necessary, repair fault and erase fault memory.
  , interrogating and erasing fault memory
• ‒ Then:
• ‒ Leave fault reader V.A.G 1551 connected.
• ‒ Continue running engine at idling speed.

• ‒ Input 04 for "Initiate basic setting" and confirm with Q.

• ‒ Input 01 for "Display group number" and confirm with Q.

Do not continue with check until an 8 digit number block 00000000 appears in the 4th display zone.

Note:

If at one or more positions a 1 is displayed in display zone 4, the test conditions have not been fulfilled:

; Relevance of figures in 8 digit number block

• ‒ Check ignition timing at 2000...2500 rpm.
       Specification: about 6° before TDC fluctuating1)

     1)     Up-to-date specifications:

=> "Exhaust test" binder

• ‒ Allow engine to idle for at least 1 minute.
• ‒ Read Lambda voltage in display zone 3. Lambda voltage must fluctuate by
       more than 0.3 V.
  
• ‒ End the engine basic setting by pressing the⇒ button. When doing this the radiator fan must not run.
• ‒ Input 06 for "End output" and confirm with Q.

If the specifications are not obtained:

• ‒ Check air intake system for leaks (leakage air)
  => Page 24-72 .
• ‒ Check exhaust system between cylinder head and catalyst including CO sampling pipe for leaks.
• ‒ Check Lambda probe and Lambda control.
• ‒ Carry out road test, then repeat fault memory interrogation and basic setting.