SEAT Workshop Service and Repair Manuals

Special tools, testers, measuring instruments and auxiliary items required

• ◆ 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

• ● Battery voltage at least 11.5 V

• ● Fuse No. 18 OK.
• ● Fuel pump relay OK

Test sequence

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

• ‒ → Check probe heating at Lambda probe connector contacts 1+2 for continuity
      Specification: max. 200 ω

If the specification is not attained:

• ‒ Renew Lambda probe (G39)
  =>Page 24-9, item 6.

If the specification is attained:

• ‒ → Connect multimeter to measure voltage at contacts 1+2 of connector to Motronic control unit.
• ‒ Start engine and run at idling speed
      Specification: At least 11.5 V
• ‒ Switch off ignition

If no voltage is present:

• ‒ Remove dash panel insert:

=> Electrical system; Repair group 90

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

• ‒ → Check wiring between test box and 4 pin connector for open circuit according to current flow diagram.
      Contact 2+socket 12
      Wire resistance: Max. 1.5 ω

If the specification is attained:

• ‒ Check wiring from contact 1 to relay plate according to current flow diagram.