Audi Workshop Service and Repair Manuals

Checking activation

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
• ◆ Diode test lamp V.A.G 1527
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Check conditions

• ● The fuses must be OK.
• ● Earth connection between engine (on gearbox bell housing) and body (below battery) OK.
• ● The battery voltage must be at least 11.5 V.

• ● Engine speed sender must be OK, checking Page 24-63.
• ● Hall sender must be OK, checking
  .

• ● Fuel pump relay must be OK

Test sequence

• ‒ → Pull 4 pin connector off ignition transformer -arrow-.

• ‒ → Pull plugs -arrows- off all injectors.

• ‒ → Connect diode test lamp V.A.G 1527 using aux. cables from V.A.G 1594 to connector contacts of Cyl. 1.
• ‒ Operate the starter and check the voltage supply for No. 1 cylinder injector.
      The LED must light up
• ‒ Repeat check at the injector connectors for Cyls. 2...4.
• ‒ Switch off ignition.

If the LED does not light up on any cylinder:

• ‒ → Connect diode test lamp to Cyl. 1 connector, contact 1 and earth.
      The LED must light up
• ‒ Repeat check at the injector connectors for Cyls. 2...4.

If the LED does not light up:

• ‒ Switch off ignition.
• ‒ Check wire between 2 pin connector contact 1 and fuel pump relay (J17) for open circuit according to current flow diagram.
      Wire resistance: max. 1.5 ω

If the LED does not light up on one or several cylinders:

• ‒ → Connect test box V.A.G 1598/22 to control unit wiring harness
  .

• ‒ → Check wires between test box and 2-pin connectors for injectors (connector to control unit) for open circuit using current flow diagram.
      Injector 1: contact 2+socket 79
      Injector 2: contact 2+socket 59
      Injector 3: contact 2+socket 73
      Injector 4: contact 2+socket 65
      Injector: max. 1.5 ω
• ‒ Additionally check wires for short to one another, to vehicle earth and to battery positive.
      Specification: ∞ω

• ‒ Check wiring between connector contacts 1 of injectors for open circuit to one another.
      Wire resistance: Max. 1.5 ω

Checking resistance of injectors

Test sequence

• ‒ → Check resistance of injectors between contacts.
      Specification: 12...17 ω

Note:

The resistance figures are valid for approx. 20 °C. At higher temperatures the resistance figures will increase.

If the specification is not attained:

• ‒ Renew defective injector
  Page 24-18, item 5.

Perform installation of injectors in reverse order. When doing this note the following:

• ◆ Renew O-rings on all injectors and lightly moisten with clean engine oil.
• ◆ Insert injectors vertically and in the correct position into the fuel rail and secure with retaining clips.
• ◆ With injectors secured to fuel rail, fit fuel rail on cylinder head and press in evenly.

Checking spray pattern and for leaks

Special tools, workshop equipment, test and measuring appliances and auxiliary items required

• ◆ V.A.G 1331 Torque wrench (5...50 Nm)
• ◆ V.A.G 1594 A Adapter set
• ◆ V.A.G 1630 Digital potentiometer
• ◆ Measuring container

Test conditions

• ● The fuel pressure must be in order, checking
  => Page 24-77, checking fuel pressure regulator and holding pressure.

Test sequence

• ‒ → Pull 4 pin connector off ignition transformer -arrow-.

• ‒ → Pull the 4 pin connector off coolant temperature sender (G62) with coolant temperature gauge sender (G2) -arrow-.

• ‒ → Connect digital potentiometer V.A.G 1630 using aux. cables from V.A.G 1594 to connector contacts 1+3 and set connected side to 15 kω.
• ‒ Unclip injector wiring harness on fuel rail.
• ‒ Remove fuel rail complete with injectors from cylinder head (fuel hoses remain connected)
  => Page 24-11, item 11.

• ‒ → Hold a small container under the injector to be checked and pull connectors off all other injectors.
• ‒ Have 2nd person operate starter. Injector must spray in pulses.

• ‒ Repeat check with other injectors ensuring that injector to be checked is only connected.
• ‒ Switch off ignition and afterwards check injectors for leaks. No more than
      2 drops/min
  may leak from each injector.

If the fuel loss is greater:

• ‒ Switch off ignition.
• ‒ Renew defective injector
  Page 24-18, item 5.

Perform installation of injectors in reverse order. When doing this note the following:

• ◆ Renew O-rings on all injectors and lightly moisten with clean engine oil.
• ◆ Insert injectors vertically and in the correct position into the fuel rail and secure with retaining clips.
• ◆ With injectors secured to fuel rail, fit fuel rail on cylinder head and press in evenly.