1. Examine the coil. If there are chips, cracks, signs of overheating or oil leakage on the plastic cover, the coil must be replaced.
2. Check the resistance of the primary winding of the coil. To do this, connect an ohmmeter to the low voltage terminals of the coil. At 25°C, the resistance should be 0.4–0.5 ohms. If the resistance is not as specified, replace the coil.
3. Check the resistance of the secondary winding of the coil. To do this, connect an ohmmeter to the high voltage terminal and the low voltage terminal "IN" coils. At 25°C, the resistance should be 4.5-5.5 kOhm. If the resistance is not as specified, replace the coil.
4. Check the insulation resistance for "mass". To do this, connect an ohmmeter to the coil body and in turn to each of the terminals. In all cases, the ohmmeter must show a resistance of at least 50 MΩ. If the resistance is less, replace the coil.