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, 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

• ● The battery voltage must be at least 11.5 V.

Test sequence

• ‒ → Separate white 3 pin connector to engine speed sender -arrow-.
• ‒ Measure sender resistance between connector contacts 1+2.
       Specification: 480... 1000 ω
• ‒ Check the sender for short between contacts 1+3 also 2+3.
       Specification: ∞ω

If the specifications are not obtained:

• ‒ Replace engine speed sender (G28).

If no sender fault is detected:

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.
       Contact 1+socket 67
       Contact 2+socket 68
       Contact 3+socket 56
       Wire resistance: Max. 1.5 ω
• ‒ Additionally check wires for short to one another.
       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 .