Fuel Injectors, Checking

Special tools and equipment
- VAG1551 scan tool or VAG1552 mobile scan tool with VAG1551/3B cable
- VAG1598/31 test box
- VAG1526 hand multimeter or VAG1715 multimeter
- VAG1527 voltage tester
- VAG1594 adapter set
- Wiring diagram

Check conditions
- Engine speed sensor must be OK, checking. Testing and Inspection
- Fuel pump relay must be OK







- All fuses must be OK.

Test Sequence
- First check the activation of the injectors via Output Diagnostic Test Mode. Refer to "Scan Tool Testing/Activating Actuators(Output Diagnostic Test Mode)" under "Computers and Control Systems" Testing and Inspection

If one or more injectors do not click:

Checking resistance of injectors







- Check resistance of injectors between contacts.
Specification: 12 to 17 Ohm


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


If the specification is not attained:
- Replace faulty injector

Pay attention to the following when installing the injectors:
- Replace 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.
- Set fuel distributor with secured injectors on cylinder head and press in evenly.
- The connectors must audibly engage in the injectors when pushed on.

- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory,Checking and Erasing DTC Memory. Refer to "Displaying and Reading Trouble Codes/With Manufacture Scan Tool/Check DTC Memory (Function 02)" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again: Refer to "Monitors, Trips and/or Drive Cycle/ Reading Readiness Code" Testing and Inspection
Engine code AWW, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
Engine code AWP, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection

Checking voltage supply







- Pull connectors off injectors.
- Connect voltage tester to contact 1 and Ground (GND) of relevant injector connector.
- Operate starter and check voltage supply for injector.
The LED must light up

If the LED does not light up:
- Switch ignition off.
- Check wire between 2 pin connector contact 1 and fuel pump relay (J17) for open circuit using wiring diagram.
Wire resistance: max. 1.5 Ohm

Checking activation and voltage supply







- Pull connectors off injectors.
- Connect the VAG1527 voltage tester to the connector contacts of the injector to be tested using adapter cables from VAG1594.
- Operate starter and check the activation for the injector.
The LED must flicker

If the LED does not flicker:
- Switch ignition off.
- Connect VAG1598/31 test box to control module wiring harness. The engine control module remains disconnected.







- Check the wiring between the test box and connector for open circuit, short circuit to Ground (GND) or positive using wiring diagram:
Injector 1: contact 2+socket 96
Injector 2: contact 2+socket 89
Injector 3: contact 2+socket 97
Injector 4: contact 2+socket 88
Wire resistance: max. 1.5 Ohm

If no fault can be found in the wiring:
- Replace engine control module.