SEAT Workshop Service and Repair Manuals

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

Check conditions

• ● Coolant temperature at least 80 °C
• ● Exhaust system between catalyst and cylinder head free of leaks

Functional check

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit (address word 01); carry out selection at idling.
  

• ‒ Input 08 for "Read measured value block" function and confirm with Q.

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

Only continue with the test when

• ● The coolant temperature is above 80 °C
  -Display zone 2-

• ‒ Press C key.
• ‒ Input 04 for "Display group number" and confirm with Q.

• ‒ Observe Lambda probe adaption value (additive) in display zone 3. The display must fluctuate in the range
      -22.5...22.5 %.
• ‒ Press ⇒ key.
• ‒ Input 06 for "End output" and confirm with Q.
• ‒ Switch off ignition

If the Lambda control does not fluctuate as stated:

• ‒ Check Lambda probe heating => Page 24-39.
• ‒ Check Lambda probe for soot. Renew if necessary => Page 24-9, item 6.
• ‒ Check intake air system for leaks
  => Page 24-102.

Checking Lambda probe wiring

• ‒ Remove dash panel insert:

=> Electrical system; Repair group 90

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.

• ‒ → Separate 4 pin connector to Lambda probe -arrow-.

• ‒ Check wiring between test box and 4 pin connector for open circuit according to current flow diagram.
      Contact 3+socket 42
      Contact 4+socket 20
      Wire resistance: Max. 1.5 ω
• ‒ → Check wiring at 4 pin connector for short to one another.
      Contact 1+socket 12
      Contact 1+socket 20
      Contact 1+socket 42
      Contact 2+socket 20
      Contact 2+socket 42
      Contact 3+socket 20
      Specification: ∞ω

• ‒ → Check screening -test box socket 56- for short to the probe wiring according to current flow diagram.
      Contact 2+socket 56
      Contact 3+socket 56
      Contact 4+socket 56
      Specification: ∞ω

If the specification is not attained:

• ‒ Check wiring according to current flow diagram.

If no wiring fault is detected:

• ‒ Renew Lambda probe (G39)
  , item 6.