Volkswagen Workshop Service and Repair Manuals

The needle lift sender signal is used to determine the commencement of injection. If it fails the commencement of injection switches to open-loop control (according to engine speed and engine load). During normal operation the commencement of injection is controlled by a closed-loop function (according to engine speed, engine load and temperature).

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

• ◆ 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 sequence

• ‒ Switch off ignition.
• ‒ Disconnect connector for needle lift sender => Fitting location overview, Page 23-4 .
• ‒ → Measure resistance between connector contacts.
       Specification: 80...120 ω

If the specification is not obtained:

• ‒ Replace injector cylinder 3 with needle lift sender (G80).

If the specification is obtained:

• ‒ Connect test box .
• ‒ → Check wiring between test box and connector for open circuit according to current flow diagram.
       Contact 1+ socket 12
       Contact 2+ socket 11
       Wire resistance: max. 1.5 ω
• ‒ Additionally check wires for short to one another, to vehicle earth and to battery positive.
       Specification: ∞ω

If no wiring fault is detected:

• ‒ Renew Diesel direct injection system control unit (J248) .