Tesla Automotive Error Code CC_a042: How to Fix It

Q: What does Tesla error code CC_a042 mean?

CC_a042 means Tesla's charging system detected that the AC voltage supplied by the charger or outlet was outside the acceptable range — either too low (voltage sag) or too high (voltage spike). Tesla stops charging automatically to protect the battery pack and onboard electronics from potential damage caused by abnormal voltage levels.

Q: Is CC_a042 a Tesla car problem or a charger problem?

In the majority of cases, CC_a042 is caused by the external charging equipment or your home's electrical supply rather than the Tesla vehicle itself. Common culprits include a weak or failing circuit breaker, undersized wiring, a faulty EVSE (home charger), or a public charger with grid voltage issues. If the error only happens at one location, the problem is almost certainly external. If it happens everywhere you charge, the Tesla's onboard charger module may need inspection.

Q: Can I still drive my Tesla after getting a CC_a042 error?

Yes. CC_a042 only stops charging — it does not affect your Tesla's ability to drive. Your vehicle will continue to function normally using whatever charge remains in the battery. However, you should resolve the charging issue promptly to avoid being stranded with a depleted battery.

Q: Why does CC_a042 only happen at night when I charge at home?

Nighttime voltage fluctuations are common in residential neighborhoods when grid demand peaks or other high-draw appliances (HVAC, electric dryers, other EVs) are running simultaneously on the same circuit or nearby circuits. This causes voltage to sag below Tesla's acceptable minimum. Solutions include scheduling charging during off-peak hours, having an electrician verify your dedicated EV circuit is properly sized, or enabling Tesla's scheduled charging feature to avoid peak demand windows.

Q: How do I prevent Tesla CC_a042 from happening again?

The best preventive measures are: (1) Have a licensed electrician install a properly sized dedicated 240V, 50- or 60-amp circuit for your home EVSE. (2) Use a high-quality, UL-listed Level 2 EVSE rather than a basic extension cord or shared outlet. (3) Keep your Tesla's software updated so you have the latest charging firmware. (4) If you live in an area with known utility voltage issues, consider asking your utility company to check the service voltage at your meter. (5) Periodically inspect your charging cable and connector for wear or corrosion.

Abstract

Tesla error code CC_a042 appears when your vehicle's onboard charging system detects that the incoming voltage from the charging source falls outside the acceptable range — either too high or too low. This safety mechanism stops charging to protect your battery and power electronics from potential damage. In most cases, the issue stems from the charging equipment, your home electrical supply, or a public charger problem rather than the Tesla itself.