volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

ABOUT US
Checking injectors > < Idling speed boost

Polo Mk3

Motronic injection and ignition system
Servicing injection system
Checking air conditioner and air conditioner compressor signals

These signals from the air conditioner cause the initial control value for the idling stabilization to be increased when the air conditioner compressor switches in. Thereby the idling stabilization remains in the middle of the regulating range.

Special tools, testers, measuring instruments and auxiliary items required

  • ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with 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

Test conditions

  • ● Air conditioner functioning OK.
  • ● Air conditioner must be switched off
  • ● No faults must be stored in fault memory
    , interrogating fault memory
  • ● Vehicle at room temperature (warmer than + 15 °C).

Test sequence

  • ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
    (Connecting fault reader and selecting engine control unit => Page 01-4 .)
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
 
→ Indicated on display:
Read measured value block     HELP
Input display group number XXX
  • ‒ Press keys 0, 0 and 1 for "Display group number 1" and confirm entry with Q key.
 
→ Indicated on display:
(1...4 = Display zones)
Read measured value block     1     ⇒
     1     2     3     4
  • ‒ Observe 8 digit number block in display zone 4. 3rd position from left must display 0.
         Display: 00000000
  • ‒ Switch on air conditioning system.
  • 3rd position from left must now display 1
         Display: 00100000
  • ‒ Change to display group 4. To do this press:
         V.A.G 1551: key 3 three times
         V.A.G 1552: key ↑ three times
 
→ Indicated on display:
(1...4 = Display zones)
Read measured value block     4     ⇒
     1     2     3     4
  • ‒ Select lowest temperature and highest blower speed.
 
N24-0137
  • ‒ Observe 8 digit number block in display zone 4. 2nd position from right must display 1.
         Display: 01000011

If the display does not change:

  • ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
  • ‒ Check wiring between test box sockets 35 and air conditioner for open circuit according to current flow diagram.
         Wire resistance: Max. 1.5 ω

Checking injectors > < Idling speed boost