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Volkswagen Workshop Service and Repair Manuals

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Checking engine speed sender > < Checking coolant temperature sender

Golf Mk3

Digifant injection and ignition system (4-valve)
Digifant injection and ignition system
Checking intake air temperature sender

Special tools, testers and auxiliary items

  • ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with
         ▸ 07.93: Cable V.A.G 1551/1
         08.93 ▸: 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
  • ◆ Adapter set V.A.G 1594
  • ◆ Current flow diagram
  • ◆ Chilling spray (commercially available)

Test sequence

  • ‒ Connect the fault reader V.A.G 1551 (V.A.G 1552) and with ignition switched on select engine electronics control unit with the "Address word" 01.
    (Connecting fault reader and selecting engine electronics control unit .)
  • ‒ When the engine electronics control unit registers, note the control unit version.
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Input 08 for "Read measured value block" function and confirm with Q key.
 
→ Indicated on display:
Read measured value block     HELP
Input display group number XX
  • ‒ Enter "Display group number" and confirm with Q key:
         Digifant 3.0 = 03
         Digifant 3.2 = 02
 
→ Indicated on display:
(1...4 = Display zones)
Read measured value block 2 (3)     ⇒
     1     2     3     4
  • ‒ Observe intake air temperature figure.
         Digifant 3.0 = Display zone 3
         Digifant 3.2 = Display zone 4

Display

Cause

Continuation of check

-40 °C

Open circuit or short to positive

=> Page 24-56

120 °C

Short to earth

=> Page 24-57

Approx. ambient temperature1)

---

=> Page 24-58

     1)     If a temperature is displayed which deviates greatly from the ambient temperature of the sender, check sender wiring for transfer resistances.

Continuation of check when display -40 °C:
 
N24-0101
  • ‒ → Pull 2 pin connector -1- off intake air temperature sender (G42) -2-.
  • ‒ Bridge connector contacts with aux. cables from V.A.G 1594 and observe display.

Display 120 ° C:

  • ‒ Replace intake air temperature sender -2-.

Display -40 ° C:

  • ‒ Press ⇒key.
  • ‒ Input 06 for "End output" and confirm with Q key.
  • ‒ Switch off ignition.
 
N24-0094
  • ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
  • ‒ Check wire between test box socket 36+2 pin connector contact 1 for open circuit according to current flow diagram.
         Wire resistance: Max. 1.5 ω
  • ‒ Additionally check wire for short to battery positive.
         Specification: ∞ω

If no fault in wire is detected:

  • ‒ Renew Digifant control unit (J169)
    , item 11 .
 
N24-0100

Continuation of check when display = 120 °C:

  • ‒ → Pull 2 pin connector -1- off intake air temperature sender (G42) -2-.

Display -40 ° C:

  • ‒ Replace intake air temperature sender -2-.

Display 120 ° C:

  • ‒ Press ⇒key.
  • ‒ Input 06 for "End output" and confirm with Q key.
  • ‒ Switch off ignition.
  • ‒ Pull connector off Digifant control unit.
  • ‒ Check wiring to control unit connector at 2 pin connector contact 1 for short to wire contact 2 and to vehicle earth.
         Specification: ∞ω

If no wiring fault is detected:

  • ‒ Renew Digifant control unit (J169)
    , item 11 .

Continuation of check when display = ambient temperature:
 
V24-1006
  • ‒ → Remove intake air temperature sender G42) (plug remains connected).
  • ‒ Note intake air temperature figure.
         Digifant 3.0 = Display zone 3
         Digifant 3.2 = Display zone 4
  • ‒ Spray sender with a commercial chilling spray and at the same time observe the temperature figure. The temperature figure must
         decrease.
  • ‒ Press ⇒key.
  • ‒ Input 06 for "End output" and confirm with Q key.

Checking engine speed sender > < Checking coolant temperature sender