With Manufacturer's Scan Tool

Fuel Injectors, Checking

Special tools and equipment
- V.A.G1551 scan tool (or VAG1552 mobile scan tool) with VAG1551/3 cable
- VAG1598/31 test box
- Multimeter Fluke 83 or equivalent
- VAG1527 voltage test lamp
- VAG1594 connector test kit
- Wiring diagram

Test requirements
- Engine speed (RPM) sensor must be OK, Refer to "Engine Speed (RPM) Sensor" Testing and Inspection
- Fuel Pump (FP) relay must be OK.






- All fuses must be OK.

Test sequence
- First, test activation of the fuel injectors via output Diagnostic Test Mode (DTM). [1][2]Output Diagnostic Test Mode (DTM), (Function 03)

If one or more injectors do not click:

Checking voltage supply

NOTE: Upper part of intake manifold must be removed for electrical test of fuel injectors/wires from cylinder 2 and 3.

- Disconnect fuel injector connectors.






- Connect diode test lamp to connector of tested fuel injector terminal 1 and Ground (GND).
- Switch on starter and test voltage supply for fuel injector.
LED must light up.

If LED does not light up:
- Switch ignition off.
- Check wire between 2-pin connector terminal 1 and Fuel Pump (FP) relay -J17- for open circuit according to wiring diagram.
Wire resistance: max: 1.5 Ohms

Activation and voltage supply, checking

- Disconnect fuel injector connectors.
- Use adapter cables from the VAG1594 connector test kit to connect VAG1527 diode test lamp to the connector terminals of the fuel injector to be tested.
- Switch on starter and test activation of fuel injector.
LED should flicker.

If LED does not flicker:
- Switch ignition off.
- Remove wiper arms and wind cowl






- Connect VAG1598/31 test box to control module wiring harness. Engine Control Module (ECM) is not connected.






- Use wiring diagram to check wires between test box and harness connector for open circuits or short circuits to Ground (GND) or B+.
fuel injector 1: Terminal 2+socket 96
fuel injector 2: Terminal 2+socket 89
fuel injector 3: Terminal 2+socket 97
fuel injector 4: Terminal 2+socket 88
Wire resistance: max: 1.5 Ohms

If wiring is OK:

Resistance values of fuel injectors, checking






- Test resistance of fuel injectors between terminals.
Specification: 14 to 18 Ohms

NOTE: Resistance value is valid at approx. 20°C. At higher temperatures, resistance value increases.

If specified value is not obtained:
- Replace defective fuel injector.
- Erase DTC memory to bring adaptation values into a neutral state.

If resistance values are OK and no malfunctions are found in the wires:
- Replace Engine Control Module (ECM).