Fuel Injectors, Checking

Fuel Injectors, Checking

Electrical testing
- Disconnect harness connector for fuel injector to be tested.







- Using multimeter US 1119 (Fluke 83 or equivalent), check resistance between fuel injector terminals.
Specified value: 12-20 ohms
- If resistance is not OK, replace faulty fuel injector.

Checking voltage supply
- Disconnect harness connector for fuel injector to be tested.







- Connect VAG1527B LED voltage tester between fuel injector connector terminal 1 and engine Ground.
- Switch ignition on. LED must light up.
- If LED does not light, check wiring for open circuit between terminal 1, fuse for fuel injectors (at E-box in plenum), and power supply relay.
- If LED does light, check actuation of fuel injectors.

Checking Fuel Injector Actuation







- Disconnect harness connector for fuel injector to be tested.
- Connect VAG1527B LED voltage tester between terminals 1 and 2, using adapter cables from VAG1594 connector test kit.

Initiate output Diagnostic Test Mode (DTM) and actuate fuel injectors. Refer "Scan Tool Testing/Output Diagnostic Test Mode (DTM), (Function 03)" Testing and Inspection


Output Diagnostic Test Mode ->
Injector Cyl. 1 -N30


NOTE: Output signals are checked by listening for the sound of the fuel injector being actuated, or checking by feel for mechanical evidence of actuation (clicking, vibration, etc.).







- Begin test by partially opening throttle (closed throttle position switch open).
Fuel injector will be heard and felt to click 5 times.
- All remaining fuel injectors are checked in sequence by pressing -> button on VAG1551 scan tool.
- Using this method, check all fuel injectors.
LED must light up each time.

If LED does not light:
- Connect VAG1598/19 test box to Engine Control Module (ECM) wiring harness connector. Refer "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAG1598/19 Test Box, Connecting" Testing and Inspection

- Check wiring harness for continuity or short circuit to positive (B+) between each fuel injector harness connector terminal 2 and corresponding ECM/test box socket:

Fuel injector connector VAG1598/19 test box socket
(terminal 2)
Cyl. 1 E1
Cyl. 2 D7
Cyl. 3 D6
Cyl. 4 E2
Cyl. 5 E5
Cyl. 6 D2
Cyl. 7 D3
Cyl. 8 E6







- Repair open circuit or short circuit as necessary.

If voltage supply and fuel injector actuation are OK:
- Replace ECM.
- Generate new readiness code. Refer "Monitors, Trips and/or Drive Cycle (Readiness Code)/Generating, Readiness Code" Testing and Inspection