P0620Medium urgency
Generator Control Circuit Malfunction
Electrical · Charging System
⚠️ Fix soon — battery will discharge without functioning alternator.
What this means
The alternator (generator) control circuit has a fault. The ECM controls alternator output on modern vehicles. A fault here can prevent proper charging or cause overcharging.
Likely causes
- Failed alternatorMost common
- Wiring fault in alternator control circuitCommon
- Faulty ECM outputLess common
Estimated repair cost
Alternator replacement$300 – $800
Wiring repair$75 – $250
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Frequently asked questions
What does P0620 mean?
The alternator (generator) control circuit has a fault. The ECM controls alternator output on modern vehicles. A fault here can prevent proper charging or cause overcharging.
Is P0620 serious?
Fix soon — battery will discharge without functioning alternator.
How much does it cost to fix P0620?
Repair costs for P0620 range from $300 – $800 depending on the root cause and your vehicle.
Can I drive with P0620?
You can drive short distances but should have it repaired within 1-2 weeks to prevent further damage.