Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1527 B
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31

Checking internal resistance

• ‒ → Remove engine cover -arrows-.

• ‒ Unplug connector on injector to be checked.

• ‒ → Connect multimeter to injector to measure resistance.
• ‒ Specified value: 13.5...15.5 ω

When the engine is at operating temperature the resistance is increased by approx. 4...6 ω.

If specified value is not attained:

• ‒ Replacing injector

Checking power supply

Test requirements:

• ● Fuse for injectors OK.

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

• ● Fuel pump relay OK; checking .

• ‒ Unplug connector on injector to be checked.

• ‒ → Connect voltage tester V.A.G 1527 B as follows:

• ‒ Switch the ignition on.
• ‒ The LED should light up.

If the LED does not light up:

• ‒ Check wiring connection between contact 1 and fuse for injector for open circuit:

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

• ‒ Rectify open circuit, if necessary

If the LED lights up:

• ‒ Check actuation.

Checking actuation

Test requirements:

• ● Internal resistance of the valve OK

• ‒ → Push back rubber grommet of plug -arrow- of injector but leave plug attached.
• ‒ Connect up voltage tester V.A.G 1527 B between receptacles 2 (signal) and 1 (positive).
• ‒ Operate the starter briefly (the engine may start).
• ‒ The LED should flash.

Note:

Voltage testers with a low current draw continue to glow faintly between actuation from the engine control unit (rather than extinguishing completely) and become slightly brighter when actuated.

If LED does not flash:

• ‒ Connect the V.A.G 1598/31 test box to wiring harness leading to engine control unit; the engine control unit should not be connected => Page 24-17.

• ‒ → Check for open circuit and short to positive or earth in the following wiring connections:

• ‒ Rectify any open/short circuit as necessary.

If the wiring is OK:

• ‒ Fit a new engine control unit => Page 24-22.