How to Test And replace Fuel Injectors on Audi A4 & VW passat models?

The Procedure is exactly similar for Both Audi A4 and Vw passat car models.

Fuel Injectors
Details with Diagrams are mentioned below:----

1.8L, 2.0L
  1. Turn the ignition switch OFF and remove the keys
  2. Release the fuel system pressure. See 'Relieving Fuel System Pressure'
  3. Remove or disconnect the following:
  4. Fuel lines from the fuel injector rail
    Fuel rail bolts
    Fuel rail, with injectors
To install
  1. Installation is the reverse order of the removal procedure. Note the following:
    1. Always replace the gasket (below the lower insert) before the fuel injectors are installed.
    2. Before the upper insert is installed, clean the threads and apply a light coat of thread-lock compound.
6-Cylinder Engines
  1. Remove the engine cover
  2. Remove the air intake hose between the mass airflow sensor and intake air elbow
  3. Remove all harness connectors to injectors
  4. Disconnect vacuum hose from fuel pressure regulator
  5. Expose wires at fuel rail

Fig. Removing the fuel injector rail
  1. Unscrew fuel rail from intake manifold (arrows)

Fuel system is under pressure! Place a cloth around the connection point before opening the system. Then release pressure by carefully loosening connection.

  1. Disengage retaining clip and remove the injector
To install
  1. Installation is in reverse order of removal, noting the following:
    1. Remove the O-rings from all opened connections. NEVER remove the plastic cap from valve head to replace front O-ring; pry the O-ring off over the plastic cap.
    2. Lightly lubricate the O-ring with clean engine oil.
    3. Make sure all the injectors are in place and seated correctly.
    4. Check the clip to ensure an unobstructed fitting on injector.
    5. Place the fuel rail with injectors into the intake manifold, and apply uniform pressure to press it in.


1.8L, 2.0L, 2.8L (V6 & Vr6)
Fuel Injector Electrical Diagnosis And Activation

Fire hazard! Do NOT smoke or work near heaters or open flame. Do NOT have anything nearby that could ignite fuel. The fuel system is under pressure. Before opening, cover connections with a rag, and open carefully to release pressure.

  1. Obtain the following special tools and equipment:
  2. VAG 1551 or VAG 1552 scan tool, with VAG 1551/3 adapter cable
    Audi A4, VW 1594 test kit
    VAG 1598/22 test box
    Multimeter US1119 (Fluke 83, or equivalent)
    VAG 1348/3A remote control, with adapter cable VAG1348/32
    VAG 1527B LED voltage tester
    VAG 1602 measuring glass from calibration tester
    Wiring diagram for the specific vehicle and engine being tested
  3. Verify that the engine speed sensor and fuel pump are operational.
  4. Remove all components necessary for access to the fuel injectors.
  5. Using the scan tool, run the 'Diagnostic Test' mode for actuating the fuel injectors.
  6. If one or more injectors Do NOT click, perform the following tests:
    1. Disconnect the 5-pin harness connector from ignition coil.
    2. Disconnect the harness connectors (1) from all injectors (2).
    3. Connect the VAG 1527B LED voltage connector terminals for cylinder/fuel injector, using the adapter cables from VW1594 connector test kit.
    4. Operate the starter and check voltage supply for cylinder No. 1 fuel injector.
    5. The LED must flicker.
    6. Repeat the test for all remaining injectors.
    7. Turn the ignition switch off.
    8. Connect the VAG1527B LED voltage tester to cylinder No. 1 harness connector terminal No. 1 and ground.
    9. Operate the starter.
    10. The LED must light.
    11. If the LED does not light, switch the ignition OFF and check the wire between the 2-pin connector terminal No. 1 and the fuel pump relay for an open circuit. The specified value is 1.5 ohms (maximum).
    12. Connect the VAG 1598/22 test box to ECM harness connector.
    13. Check the wiring for open circuits between the ECM/test box and each fuel injector.
    14. Check the wiring for short circuits between all circuit wires and connector terminals.
    15. Check the wiring between connector terminal No. 1 of all injectors and ground for open circuit.

Click image to see an enlarged view
Fig. Disconnecting the harness from all injectors

Click image to see an enlarged view
Fig. Checking for a proper ground, using VAG 1527B tester

Click image to see an enlarged view
Fig. Connecting the test box VAG1598/22 to the ECM harness
  1. To check for fuel injector resistance perform the following:
    1. Remove the harness connector from each injector.
    2. With a DVOM, check the resistance at each fuel injector. Specified resistance is 13.5-15.5 ohms.
    3. If the injector is not within specification, replace the injector.
Fuel Injector Leak Test

Verify proper operation of the fuel pressure regulator prior to performing these tests.

  1. Remove all components necessary in order to remove the fuel rail and attached injectors.
  2. Remove the injector rail and injectors as an assembly. Support this assembly out of the way above the manifold.

Leave the injector harness attached to injectors.

  1. Conduct an output Diagnostic Test Mode (DTM), actuating the No. 1 cylinder fuel injector. The fuel pump must be running.

This step allows the fuel pump to run without the engine running. The closed throttle position switch must be closed during the test, or the selected injector will be activated 5 times, discharging fuel.

  1. Visually check fuel injector for leaks. A maximum of 1 to 2 drops per minute per injector.
  2. If leak exceeds allowed amount, switch the ignition key OFF and replace the injector.

Always replace the seals.

These details will help.


Car repair guide?


No comments:

Post a Comment