SEAT Workshop Service and Repair Manuals

The engine speed sender (G28) is a speed and reference mark sender. The engine will not start if there is no speed signal. If the speed signal fails when the engine is running, it will cause the engine to stall immediately.

Special tools, workshop equipment, 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 1598/31
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594

• ◆ Current flow diagram

Test sequence

• ‒ → Separate grey 3 pin connector -1- to engine speed sender.

• ‒ → Connect multimeter V.A.G 1526 using aux. cables from V.A.G 1594 to connector contacts 2 and 3 of engine speed sender
      Specification: approx. 730...1000 ω

Note:

The resistance figures are valid for approx. 20 °C. At higher temperatures the resistance figures will increase.

• ‒ Check the sender for short between contacts 1 + 2 as well as 1 + 3.
      Specification: ∞ω

If the specifications are not obtained:

• ‒ Renew engine speed sender (G28).

If no sender fault is detected:

• ‒ Remove battery.
• ‒ → Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.

• ‒ → Check wiring for open circuit between test box and 3-pin connector using current flow diagram.
      Contact 1+test box socket 108
      Contact 2+test box socket 90
      Contact 3+test box socket 82
      Wire resistance: Max. 1.5 ω
• ‒ Additionally check wires for short to one another.
      Specification: ∞ω

If no fault is detected in the wiring:

• ‒ Remove sender and check sender that wheel is fitted securely and not damaged.

Note:

There is a larger gap on the sender wheel. This gap is the reference mark and does not mean that the sender wheel is damaged.

If no fault is detected on sender wheel:

• ‒ Renew engine control unit .