Volkswagen 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 1598/22

• ◆ 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.
• ‒ Measure sender resistance between contacts 2 + 3 of connector to sender.
       Specification: 480...1000 ω
• ‒ 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:

• ‒ → Connect test box V.A.G 1598/22 to control unit wiring harness.
• ‒ Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.
       Contact 1+socket 67
       Contact 2+socket 63
       Contact 3+socket 56
       Wire resistance: Max. 1.5 ω
• ‒ Additionally check wires for short to one another.
       Contact 1+socket 63
       Contact 1+socket 56
       Contact 2+socket 67
       Specification: ∞ω

If no wiring fault is detected:

• ‒ Remove sender and check sender wheel for secure fit, damage and run-out.

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 electronics control unit .