Checking the voltage supply to the fuel injectors (VW Passat B5)

Location of electrical connector (1) supplying voltage to the fuel injector and connector (2) on the fuel injector

Execution order

1. Disconnect the electrical connector from the fuel injector of the first cylinder, see Fig. Location of the electrical connector (1) supplying voltage to the fuel injector and the connector (2) on the fuel injector.

2. Connect the control LED to the contacts of the connector (1) (see Fig. Location of the electrical connector (1) for supplying voltage to the fuel injector and the connector (2) on the fuel injector). When the engine crankshaft is turned by the starter, the LED should flash.

3. Similarly, check the voltage supply to the remaining fuel injectors.

The LED does not blink on any of the cylinders

The location of the contacts on the electrical connector supplying voltage to the fuel injector

1. Connect the test LED to terminal #1 of the electrical connector for supplying voltage to the fuel injector and to the vehicle ground, see Fig. Location of terminals on the electrical connector for supplying voltage to the fuel injector.



2. Connect terminal No.2 of the electrical connector to the vehicle ground.

3. Turn the engine crankshaft with the starter. The LED should blink. Otherwise, check the entire electrical circuit of the fuel injectors.

The LED does not blink on only one or several cylinders

1. Check the condition of the electrical circuit for the fuel injectors and determine and eliminate the location of the electrical circuit break or short circuit to ground.

2. Check the operation of the engine control unit.

Resistance check

Ohmmeter connection points for checking fuel injector resistance

Disconnect the electrical connectors from the fuel injectors one by one and, using an ohmmeter, check the resistance of the fuel injectors, which should be between 12 and 17 ohms, see Fig. Ohmmeter connection points for checking the resistance of fuel injectors.

Warning: When the engine is warmed up to normal operating temperature, the resistance of the fuel injectors increases by 4-6 ohms.

If the fuel injector resistance is different from the specified value, replace the fuel injector.