Electrical Checks
WARNING: Fire hazard! Do not smoke, work near heaters or open flame, or have anything in the area that could ignite fuel.CHECKING ELECTRICAL RESISTANCE
- Disconnect harness connector from fuel injector to be tested.
Fuel Injector Testing:
- Measure resistance of fuel injector.
Specification:
Bosch: 15.0-17.0 ohms
Siemens: 13.5-14.5 ohms
- Replace any fuel injector for which resistance measurement does not fall within specified value.
CHECKING VOLTAGE SUPPLY
REQUIREMENTS
^ Fuel pump relay OK.
^ Activation of fuel pump relay OK.
^ Fuse for fuel injectors OK.
PROCEDURE
- Disconnect harness connector from fuel injector to be tested.
2-Pin Connector:
- Connect VAG 1527B voltage tester between harness connector terminal 1 and Ground (GND).
- Use scan tool "Output Diagnostic Test Mode" function 03 to trigger fuel pump relay -J17-.
^ Specified Value: Voltage tester must light up.
If the LED does not light up:
- Check wiring between terminal 1 and fuel injector fuse using wiring diagram.
- Repair if necessary.
If the LED lights up:
- Check fuel injector triggering.
CHECKING FUEL INJECTOR TRIGGERING
- Disconnect harness connector on fuel injector to be tested.
2-Pin Connector:
- Connect VAG 1527B voltage tester between terminal 2 and battery positive voltage (B+) using jumper wires from connector test kit VW 1594.
- Operate starter briefly (the engine can also turn over).
- Operate starter for several seconds (OK for engine to turn).
^ Specified Value: Voltage tester must flash.
If tester does not flash:
- Check wiring and connections between connector terminal 2 (for fuel injector being tested) and ECM as follows:
- Connect VAG 1598/19 test box to ECM harness connector.
- Check fuel injector 1 signal wire for continuity between harness connector terminal 2 and test box socket D1.
^ Specified Value: max. 1 Ohm.
- Check fuel injector 2 signal wire for continuity between harness connector terminal 2 and test box socket D2.
^ Specified Value: max. 1 Ohm.
- Check fuel injector 3 signal wire for continuity between harness connector terminal 2 and test box socket D4.
^ Specified Value: max. 1 Ohm.
- Check fuel injector 4 signal wire for continuity between harness connector terminal 2 and test box socket D5.
^ Specified Value: max. 1 Ohm.
- Check fuel injector 5 signal wire for continuity between harness connector terminal 2 and test box socket D6.
^ Specified Value: max. 1 Ohm.
- Check fuel injector 6 signal wire for continuity between harness connector terminal 2 and test box socket D8.
^ Specified Value: max. 1 Ohm.
If continuity is not obtained:
- Eliminate open or short circuit between terminal 2 of respective fuel injector connector, and ECM connector.
Injector Circuit Test Connections:
If voltage tester does not flash for each fuel injector:
- Check voltage supply for ECM.
If the voltage supply is OK:
- Replace ECM.