Fuel Injectors, Testing

Fuel Injectors, Checking







Special tools and equipment
- VAG1526A or Fluke 83 Multimeter
- VAG1527B Voltage tester
- VAG1594A Connector test kit
- VAG1598/31 Test box

Checking internal resistance







- Remove engine cover (arrows).
- Disconnect harness connector at fuel injector to be tested.







- Connect multimeter at valve for resistance measurement.
- Specified value: 12 ... 13 ohms (at room temperature)

If specified value is not obtained:
- Replace fuel injector.

If specified value is obtained:
- Check voltage supply.

Checking voltage supply

Requirements
- Fuse for fuel injectors OK
- Fuel Pump (FP) Relay OK
- Disconnect harness connector at fuel injector to be tested.







- Connect VAG1527B voltage tester as follows:

Harness connector Terminal Measure to
1 Engine Ground (GND)

- Switch ignition on.
- LED must light up.

If LED does not light up:
- Check wiring connection between terminal 1 and fuse for injector valves for open circuit

- Repair open circuit in wiring if necessary.

If LED lights up:
- Check activation of fuel injectors.

Checking activation

Requirement
- Internal resistance of valve OK
- Slide back rubber grommet of fuel injector connector, but leave connector connected.







- Connect VAG1527B voltage tester between sockets 2 (signal) and 1 (B+).
- Operate starter briefly (engine can also start).

- LED must blink.

NOTE: Voltage testers do not go out completely during low current pick-up between activations by the ECM, but rather continue to glow a little and then get slightly brighter during activation.

If LED does not blink:
- Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM) but do not connect ECM. Scan Tool Testing and Procedures







- Check following wiring connections for open circuit and short circuit to Ground (GND) and B+:







- Repair open circuit in wiring or short circuit if necessary.

If wiring connection is OK:
- Replace Engine Control Module (ECM).