Fuel Injector: Testing and Inspection

Fuel Injectors, Checking

Checking activation

Special tools and equipment
- VAG 1598/18 Test Box
- Fluke 83 multimeter (or equivalent)
- VAG 1527B LED tester
- VW 1594 Adapter kit
- Wiring diagram

Test conditions
- Engine speed sensor OK, checking Testing and Inspection
- Fuel pump relay OK

Test sequence

- Disconnect 5-pin harness connector from ignition coil.

- Disconnect connector -1- from connection -2- on all injectors
- Connect VAG 1527 B LED tester between Cyl. 1 injector connector terminals using jumper wires from VW 1594 adapter kit.
- Operate starter and check voltage supply to cyl. 1 injector.
- LED must flicker
- Repeat injector check for Cyls. 2 to 6.
- Switch ignition off.

If LED does not flicker for any cylinder:

- Connect LED tester between
terminal 1 and Ground for cyl. 1 connector.
- Operate starter.
- LED must light up

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

If LED flickers for one or more cylinders:

- Connect VAG 1598/18 Test Box to ECM wiring harness.

- Check wiring for open circuit between Test Box and injector connectors using wiring diagram, connect as follows:
Cyl. 1 connector, terminal 2 + socket 24
Cyl. 2 connector, terminal 2 + socket 25
Cyl. 3 connector, terminal 2 + socket 26
Cyl. 4 connector, terminal 2 + socket 2
Cyl. 5 connector, terminal 2 + socket 3
Cyl. 6 connector, terminal 2 + socket 4
- wire resistance: 1.5 Ohms maximum
- Check wires for shorting to one another
- specification: infinity Ohms
- Check for open circuit between terminal 1 of fuel injector connector.
- wire resistance: 1.5 Ohms maximum
- Check wires for shorting to one another.
- specification: infinity Ohms

Fuel injector resistance, checking

- Measure fuel injector resistance between injector terminals.
- specification: 15.0 to 21.5 Ohms

If specification not obtained:
- Replace faulty fuel injector.