volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

ABOUT US
Checking throttle valve positioner > < Checking Lambda probe

Passat (B3)

Mono-Motronic Injection and Ignition system
Mono-Motronic injection and ignition system
Checking engine operating mode

Note:

Check establishes whether Mono-Motronic control unit (J169) recognises the engine operating modes (idling, acceleration enrichment full throttle, overrun).

  • ‒ Connect fault reader V.A.G 1551 and select engine electronics control unit (address word 01); selection is carried out with engine idling.
 
→ 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 04 for display group 04 and confirm with Q.
 
→ Indicated on display:
(1...4 = Display zones)
Read measuring value block     4     ⇒
     1     2     3     4

Note:

If something different is indicated on the display =>Fault reader operating instructions.

Idling speed:
     
    → Observe 7th position from left in display zone 4.
         Specification: 1
    Read measuring value block 4     ⇒
    ...rpm     ...%...     ...km/h     01000000

    Part-load:

    • ‒ Observe 6th position from left in display zone 4.
     
    → Open throttle uniformly.
         Specification: 1
    Read measuring value block 4     ⇒
    ...rpm     ...%     ...km/h     00100000

    Acceleration enrichment

    • ‒ Observe 4th position from left in display zone 4.
     
    → Open throttle (rev-up over 3000 rpm).
         Specification: 1
    Read measuring value block 4     ⇒
    ...rpm     ...%     ...km/h     00010000

    Full throttle:

    • ‒ Observe 5th position from left in display zone 4.
           Specification: 1 (00010000)
     
    → Full throttle (rev-up)
         Specification: 1 (briefly).
    Read measuring value block 4     ⇒
    ...rpm     ...%     ...km/h     00010000

    Overrun:

    • ● Coolant temperature above 60 °C
    • ‒ Raise engine speed to above 3000 rpm.
    • ‒ Observe 8th position from left in display zone 4.
     
    → Close throttle valve abruptly.
         Specification: over 1400 rpm = 1 (briefly)
    Read measuring value block 4     ⇒
    ...rpm     ...%     ...km/h     10000000

    Note:

    Below 1400 rpm idling speed is recognised.

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

    If the specifications are not attained:

    • ‒ Interrogate and erase fault memory. Eliminate faults if necessary => Page 01-5 .
    • ‒ Check throttle valve potentiometer
      => Page 24-40 .
    <SOURCEMARKET> </SOURCEMARKET> <SOURCESYSTEM> </SOURCESYSTEM>

    Checking throttle valve positioner > < Checking Lambda probe