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

Test conditions

• ● Engine cold

Test sequence

• ‒ 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.

Functional check of sender

• ‒ Observe coolant temperature figure in display zone 2. The temperature figure must
      Increase uniformly and without interruption.

• If a temperature figure is displayed which deviates greatly from the sender's ambient temperature, check sender wiring for transfer resistances.

Notes:

• ◆ Depending upon the temperature level, the display on fault reader will jump by 1.5...5.0 °C
• ◆ If irregular engine running occurs in certain temperature ranges and the temperature figure does not increase without interruption, the temperature signal is temporarily interrupted and the sender must be renewed.
• ◆ Open circuit is indicated by -46.5 °C.

• ‒ Press ⇒ key.
• ‒ In put 06 for "End output" and confirm with Q.
• ‒ Switch off ignition

If the figure does not increase uniformly:

• ‒ Replace coolant temperature sender (G62)
  , item 7.

If a coolant temperature sender fault is indicated in fault memory even through the figure increases uniformly:

• ‒ Remove dash panel insert:

=> Electrical system; Repair group 90

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

• ‒ → Pull 2 pin connector -arrow- off coolant temperature sender.

• ‒ → Check wiring between test box and 2 pin connector for open circuit according to current flow diagram.
      Contact 1+socket 14
      Contact 2+socket 33
      Wire resistance: Max. 1.5 ω
• ‒ Check wire between control unit connector and 2 pin connector contact 2 for short to wire contact 1 and to vehicle earth, according to current flow diagram.
      Contact 2+socket 14
      Specification: ∞ω
• ‒ Additionally check wires for short to battery positive.
      Specification: ∞ω

If no wiring fault is detected:

• ‒ Perform resistance measurement at coolant temperature sender (G62) contacts 1+2, resistance figures => Page 24-17, Fig.1
• ‒ Reconnect connector.

If the specifications are not attained:

• ‒ Renew Motronic control unit (J220)
  => Page 24-8, item 2.