Audi Workshop Service and Repair Manuals

Electrical checks on injectors

• ‒ Remove the plug connector from the injector which is to be tested.
• ‒ → Measure the resistance between the injector contacts using the V.A.G 1526 hand held multimeter.

• Specified value: 13...18 ω.

If the engine is warm, the resistance will be approx. 4...6 ω.

• ‒ If the measured value is not as specified, replace the injector.

Checking the power supply to the injectors

Test conditions

• ● Fuse for injectors OK.

• ‒ Remove the plug connector from the injector which is to be tested.
• ‒ → Connect the V.A.G 1527 diode test lamp between contact 1 and the engine earth.
• ‒ Operate the starter for a few seconds (the engine can be allowed to start).

The diode test lamp should light up.

• ‒ If the diode test lamp lights up, test the actuation of the injectors.

If the diode test lamp does not light up:

• ‒ Check the wiring from contact 1 via the injector fuse to the fuel pump relay for continuity and, if necessary. rectify open circuit.

=> Current Flow Diagrams, Electrical Fault Finding and Fitting Locations binder

Checking injector actuation

• ‒ Remove the plug connector from the injector which is to be tested.
• ‒ → Connect the V.A.G 1527 diode test lamp between contact 2 and the battery's positive terminal.
• ‒ Operate the starter briefly (the engine may start briefly).

The diode test lamp should flash.

Note:

Diode test lamps with a low current consumption do not go out completely between the flashing pulses, but continue to glow slightly and become much brighter during the flashing pulses.

If the diode test lamp does not flash:

• ‒ Connect the V.A.G 1598/22 test box to the wiring harness for the engine control unit
  .
• ‒ → Check the wiring between contact 2 on the connector for the injector in question and the engine control unit for continuity or a short to positive.

• ‒ If necessary, rectify open circuit or short circuit.
• ‒ If the wiring is OK, replace the engine control unit .