Volkswagen Workshop Service and Repair Manuals

Notes:

• ◆ The engine speed sender is a combined speed sender and reference mark sender.
• ◆ The engine can run without a signal from the -G28. It is also possible (with considerable difficulty) to start the engine without a signal from the -G28 (emergency running function).

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ 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

• ‒ → Disconnect the grey connector for the engine speed sender -arrow-.

• ‒ → Connect hand multimeter V.A.G 1526 (resistance measurement) using adapter cables from V.A.G 1594 to contacts 2 and 3 of engine speed sender connector.
       Specification: Approx. 730...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 1598/22 to control unit wiring harness.

• ‒ → Check the wiring between test box and 3 pin connector for open circuit using current flow diagram.
       Contact 1+socket 70 (screening)
       Contact 2+socket 63
       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 control unit .