volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

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Checking engine operating mode > < Checking idling stabilization

Passat (B3)

Digifant Injection and Ignition System
Digifant injection and ignition system
Checking Lambda probe and Lambda control
  • ● Engine oil temperature min. 80 °C
  • ● Idling check OK., checking
  • ● Exhaust system between catalyst and cylinder head free of leaks
  • ● Lambda probe heating voltage supply OK., checking => Page 24-20
  • ‒ Connect fault reader V.A.G 1551 and select engine electronics control unit (address word 01); selection is carried out with engine idling.
    => Page 01-3
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Input 08 for "Read measured value block" function and confirm with Q.
 
→ Indicated on display:
Read measured value block     HELP
Input display group number XX
  • ‒ Input 01 for display group 01 and confirm with Q.
 
→ Indicated on display:
(1...4 = Display zones)
Read measured value block     1     ⇒
     1     2     3     4

Note:

If something different is indicated on the display:

=> Fault reader operating instructions

Do not continue with check until 00000000 appears in 4th display zone.

Note:

If one or more 1s appear in display zone 4, test conditions are not satisfied:

=>Meaning of numbers in display zone 4,

Page 24-30 .

  • ‒ Increase engine speed to approx. 2500 rpm for 1 minute, then allow engine to idle.
  • ‒ Read Lambda voltage in display zone 3. Lambda voltage must fluctuate by
         more than 0.3 V.

Display

Cause

Continuation of check

approx. 1.24 V

Open circuit

=> Page 24-34 , continued

approx. 1.60 V

Short to positive

approx. 0.00 V

Short to earth

fluctuates by more than 0.3 V

Control OK.

---
  • ‒ Press ⇒ key.
  • ‒ Input 06 for "End output" and confirm with Q.

Continuation
 
V24-1145

If 0.00 V appears in display zone 3 (earth connection):

  • ‒ Separate 4-pin connector on Lambda probe and probe heater.

If approx. 1.24 V appears in display zone 3 with connector separated:

  • ‒ Renew Lambda probe (G39).

If 0.00 V appears in display zone 3 with connector separated:

  • ‒ Perform electrical check, test step 15
    => Page 01-16 . Renew Digifant control unit (J169) if necessary.

If Lambda voltage does not fluctuate by more than 0.3 V (after checking with increased engine speed):

  • ‒ Perform electrical check, test step 15
    => Page 01-16 .
  • ‒ Renew Lambda probe (G39).

Checking engine operating mode > < Checking idling stabilization