Checking the injector needle displacement sensor (VW Polo 3)

1. Turn off the ignition.

2. Disconnect the wiring connector from the injector needle movement sensor (arrow) (Fig. 7.59).



3. Measure the resistance between the connector contacts (Fig. 7.60). Specified value: 80-120 Ohm.



4. If the specified value is not achieved, replace the third cylinder injector with the injector needle displacement sensor.

5. If the specified value is reached:

• connect the VAG 1598/22 tester to the engine control unit wiring harness (fig. 7.38);
• check the wire between the tester and the socket for open circuit: contact 1 and socket 62, contact 2 and socket 55 (Fig. 7.61). Specified value: 1.5 Ohm;
• additionally, check the wires for short circuits to each other, to the vehicle ground, and to the positive battery terminal. Specification resistance: ∞ Ohm.

6. If no fault is found in the wires, replace the engine control unit.