With Manufacturer's Scan Tool

Fuel Injectors, Checking

Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester V.A.G 1552 with cable VAG 1551/3B
- Test box V.A.G 1598/31
- 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
- Wiring diagram

Check conditions







- All fuses must be OK
- Engine speed sensor must be OK, Testing and Inspection
- Fuel pump relay must be OK
- The battery voltage must be at least 11.5 V

Test sequence
- Check activation of injectors via Output Diagnostic Test mode. [1][2][3]Output Diagnostic Test Mode (DTM) (Function 03)


If one or more injectors do not click:

Checking voltage supply


NOTE: To perform electrical check of No.2 and 3 cyl. injectors/wiring, the manifold upper part must be removed.


- Pull connectors off injectors.







- Connect diode test lamp to terminal 1 and Ground of relevant injector connector.
- Operate starter and check voltage supply for injector. LED must light up.

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

Checking activation and voltage supply
- Disconnect connectors off injectors.
- Connect diode test lamp V.A.G 1527 to the connector terminals of injector to be tested using adapter cables from V.A.G 1594.
- Operate starter and check the activation for injector. LED must flicker

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







- Connect test box V.A.G 1598/31 to control module wiring harness. Engine control module is not connected by this action.







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

If there is no malfunction in the wiring:

Checking resistance of injectors







- Check resistance of injector between terminals.
Specification: 14 to 18 Ohms


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.
- Erase DTC memory to put learned values in a neutral setting. Reading Diagnostic Trouble Codes

If the resistance values are OK and no wiring fault has been detected:
- Replace Engine Control Module (ECM).