1. Disconnect the wire from the terminal «-» battery.
2. Remove the upper engine cover (see subsection 2.1).
3. Disconnect the block II of the injector harness from the block I of the wiring harness.
4. Connect an ohmmeter to the following contacts of block 2: the first cylinder - contacts 7 and 5; the second cylinder - 7 and 3; the third cylinder - contacts 7 and 2; the fourth cylinder - pins 7 and 6. In all cases, the resistance should be about 0.5 ohms.
5. If the resistance of any unit injector differs from the specified, measure the resistance directly at the contacts of the unit injector.
6. To do this, remove the top cover of the camshaft drive belt, the cylinder head cover, disconnect the block with wires from the pump injector and measure the resistance.
7. If it again differs from the specified, replace the unit injector. If the resistance is OK, replace the injector wires.