Volkswagen Workshop Service and Repair Manuals

The engine speed sender (G28) is a speed and reference mark sender. If the speed signal fails when the engine is running, it can cause the engine to stall.

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 conditions

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

Test sequence

• ‒ → Detach black 3-pin connector to engine speed sender -arrow- (on thermostat housing).

• ‒ → Connect multimeter to measure voltage using aux. cables from V.A.G 1594 to contacts 1 (positive) and 3 (earth) on engine speed sender connector.
• ‒ Switch on ignition.
       Specification: min. 4.5 V
• ‒ Switch off ignition.

If no voltage is present:

• ‒ → 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 using current flow diagram.
       Contact 1+socket 56
       Contact 2+socket 63
       Contact 3+socket 67
       Wire resistance: Max. 1.5 ω
• ‒ Additionally check wires for short to one another.
       Specification: ∞ω

If no wiring fault is detected and voltage was present between contacts 1+3:

• ‒ Replace engine speed sender (G28)
  , item 9 .

If no wiring fault is detected and no voltage was present between contacts 1+3:

• ‒ Replace engine control unit
  .