External Charging Equipment Error Detected (Unexpected Input Voltage)
The TESLA-PCS_A073 (Tesla Power Conversion System (PCS)) EV fault code means: External Charging Equipment Error Detected (Unexpected Input Voltage). This is a minor severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $0 for the vehicle in the common case — the faulty external equipment is what needs repair or replacement. Vehicle-side repair, if it comes to that, is diagnosed and quoted by Tesla service.
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Common Symptoms
- Alert on the touchscreen: "External charging equipment error detected — Try different charging equipment"
- AC charging won't begin
- DC fast charging / Supercharging still works normally
- Driving is unaffected
Probable Causes (Ranked by Likelihood)
- The onboard charger detects input voltage at the charge port when no power was requested — the external equipment isn't switching power on/off as commanded, often a hardware issue in that equipment Likely
- Another condition affecting the external charging equipment Possible
- A condition affecting the vehicle itself (per Tesla, this alert usually points to the external equipment) Unlikely
Frequently Asked Questions
What does PCS_a073 mean on a Tesla?
Tesla's official meaning: the vehicle's onboard charger is detecting input voltage at the charge port when no power has been requested, which indicates the external charging equipment is not functioning as expected — often a hardware issue that keeps it from switching power on or off when asked. AC charging won't start; Supercharging still works.
How do I fix PCS_a073?
Try different charging equipment — per Tesla, this alert is usually about the equipment, not the car. If other equipment charges the vehicle fine, repair or replace the original unit. If the alert appears on multiple known-good chargers, schedule Tesla service.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
This is the inverse of PCS_a052: instead of no voltage when requested, the vehicle sees voltage when it did NOT request power — a sign the equipment's power switching (contactor/relay) is misbehaving.
Per Tesla's official guidance: try charging with multiple, different types of charging equipment. If the vehicle charges on other equipment, the original unit is faulty.
Supercharging is unaffected — a Supercharger or Destination Charger is a good fallback.
If the alert follows the vehicle across multiple known-good chargers, schedule Tesla service for the onboard charging path.
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_a073)
- Tesla Model Y Owner's ManualTroubleshooting Alerts (confirms PCS_a073 is documented across models)
- Tesla firmware alert reference (core-hacked/tesla-alerts-dictionary): pcs_a073community-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
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