Cannot Charge on AC — Possible Poor Grid Power Quality
The TESLA-PCS_A016 (Tesla Power Conversion System (PCS)) EV fault code means: Cannot Charge on AC — Possible Poor Grid Power Quality. This is a minor severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $0 in the common case (different outlet or equipment); electrician work billed by the job if building wiring is at fault. Vehicle-side AC-charging repair, if it comes to that, is diagnosed and quoted by Tesla service.
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Common Symptoms
- Alert on the touchscreen: "Cannot charge - Poor grid power quality possible — Retry / Try other charge location or Supercharging"
- AC charging stops or won't start
- DC fast charging / Supercharging still works normally
- Driving is unaffected
Probable Causes (Ranked by Likelihood)
- Power supply disturbances from the external charging equipment or the electrical grid interrupting AC charging Likely
- Nearby electric devices drawing a lot of power on the same supply Possible
- A condition with the vehicle itself affecting AC charging (only if the equipment and grid causes are ruled out) Unlikely
Frequently Asked Questions
What does PCS_a016 mean on a Tesla?
Tesla's official meaning: AC charging stopped because of a condition preventing AC charging — possibly power supply disturbances from the charging equipment or the electrical grid, or nearby high-draw devices. DC fast charging / Supercharging should still work normally.
How do I fix PCS_a016?
Retry, then isolate: try a different outlet with a Mobile Connector, or different equipment if using a Wall Connector. If it charges elsewhere, the original outlet or equipment is the problem — an electrician can inspect the wiring. If it fails at multiple locations with different equipment, schedule Tesla service.
Can I still Supercharge with PCS_a016?
Yes — per Tesla's official text, DC fast charging / Supercharging should still function as expected. This alert concerns AC charging only.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
If another alert appears alongside this one specifying the condition affecting AC charging, investigate that alert first — per Tesla's official guidance.
With a Mobile Connector: try a different wall outlet. If the vehicle charges, the original outlet was the problem; if not, the Mobile Connector may be.
With a Wall Connector: try different equipment (e.g. a Mobile Connector on a separate outlet). If the vehicle then charges, the Wall Connector or its wiring is at fault — have an electrician inspect the wiring connection.
Supercharging is unaffected, so a Supercharger or Destination Charger is a good fallback and a good test.
If the alert persists across multiple locations and different equipment, then the vehicle itself may be affecting AC charging — schedule Tesla service.
Sources 4
This page is built from documented references. Verify against your own service info before repair work.
- Tesla Model 3 Owner's ManualTroubleshooting Alerts (official Tesla alert text for PCS_a016)
- Tesla Model Y Owner's ManualTroubleshooting Alerts (confirms PCS_a016 is documented across models)
- Tesla firmware alert reference (core-hacked/tesla-alerts-dictionary): pcs_a016community-maintained dictionary, not an official manufacturer document
- Tessie Tesla alert statisticsthird-party Tesla alert reference with owner-telemetry frequency — not an official Tesla document
Commonly Affected Vehicles
- Tesla Model 3
- Tesla Model Y
- Tesla Model S
- Tesla Model X
- Tesla Cybertruck
Related Codes
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