With Manufacturer's Scan Tool

Fuel Injectors, Checking

Special tools, test equipment and auxiliary items
- VAG 1551 scan tool or VAG 1552 mobile scan tool with VAG 1551/3B cable
- VAG 1598/31 test box
- VAG 1526 hand multimeter or VAG 1715 multimeter
- VAG 1527 voltage tester
- VAG 1594 adapter set
- Electrical Wiring Diagram

Test conditions






- All fuses must be OK
- Engine Speed (RPM) Sensor -G28- must be OK, checking. Engine Speed (RPM) Sensor, Checking
- Battery voltage must be at least 11.5 V
- Fuel pump relay must be OK

Test sequence

Checking resistance of fuel injectors






- Disconnect connectors from fuel injectors.






- Check resistance of fuel injectors between terminals.

Specification: 12.0 to 17.0 Ohms


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


If the specification is not obtained:
- Replace malfunctioning fuel injector, item 10.

Pay attention to the following when installing the fuel injector:
- Replace O-rings on all fuel injectors and lightly moisten with clean engine oil.
- Insert fuel injectors vertically and in the correct position into the fuel rail and secure with retaining clips.
- Fit fuel rail with secured fuel injectors onto intake manifold and press in evenly.

- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes

Checking voltage supply







- Disconnect connectors from fuel injectors.







- Connect LED test light to terminal 1 and Ground (GND) of relevant fuel injector connector.
- Operate starter and check voltage supply for fuel injector.
LED must light up.

If the LED does not light up:
- Switch off ignition.
- Check wire between 2 pin connector terminal 1 and Fuel Pump (FP) Relay -J17- for open circuit using Electrical Wiring Diagram.

Wire resistance: max. 1.5 Ohms

Checking activation and voltage supply







- Disconnect connectors from fuel injectors.







- Connect VAG1527 voltage tester to connector terminals of fuel injector to be tested using cables from VAG 1594.
- Operate starter and check activation for fuel injector.
LED must flicker

If the LED does not flicker:
- Switch off ignition.
- Remove inner plenum chamber cover, left.







- Connect VAG 1598/31 test box to control module wiring harness. Motronic Engine Control Module (ECM) -J220- is not connected by this action.







- Check wiring between the test box and 2-pin connectors for open circuit, short circuit to Ground (GND) or positive using Electrical Wiring Diagram:
- 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

- Additionally check wires for short to one another.

Specification: Infinity Ohms

If there is no malfunction in the wiring and the resistance measurement
values are OK.:
- Replace Motronic Engine Control Module (ECM) -J220-.