Code PCS_a075 was reported by the “Power conversion system (PCS)” controller in the car. The letter “a” in the middle places it among entries of the alert type.
The Power Conversion System — the combined onboard charger and DC/DC converter. It handles charging from the socket and generating the 12 V supply. These codes mostly show up as slower or interrupted charging.
The most common type. The car logged the event and may have shown it on the screen. The range is wide — from something trivial that clears itself to something that needs attention.
This is how the fault is named inside the car's firmware. For codes without a description it is the most precise clue there is — the name itself says what the event is about.
The text below comes from Tesla's technical documentation. We leave it in the original English so that translation cannot shift its meaning.
PCS DCDC timed out when attempting to discharge HV bus
DCDC converter timed out when attempting to discharge HV bus
Inability to perform vehicle precharge, CHAdeMO and GB DC compatibility may be impacted
Input voltage measurement changed too much between switching cycles (only active in phase A)
Charger AC input voltage changed too much between switching cycles
Charger input line over voltage
Charger AC input voltage peak level exceeds maximum input voltage peak threshold
Reduced AC charge rate or inability to AC charge, possibly due to incompatible grid
PCS DCDC temperature sensor is reporting irrational value
DCDC converter temperature is outside expected range for more than one second
DCDC converter temperature is within expected range
Reduced available DCDC output power
PCS DCDC HV bus voltage reading differs from HVP HV bus voltage reading by an excessive amount
DCDC converter high voltage bus voltage sensor mismatches high voltage processor's sensed value on CAN for more than three seconds
DCDC converter high voltage bus voltage sensor matches high voltage processor's sensed value on CAN for more than 500ms
Copy it exactly, letter and number included. Photographing the screen is safest — codes often differ by a single digit, and mixing them up leads somewhere else entirely.
Some codes clear after a screen restart or after the car sits locked for a few hours. If the code does not come back, it was usually a one-off glitch.
A one-off entry and a code that appears after every drive are two different things. It helps a service centre enormously if you know exactly when it shows up.
With airbags, brakes, steering and high voltage there is no point waiting it out. With the other groups you can watch and see whether the code returns at all.
Error codes are only part of the picture. For cars on TesList you also see battery health pulled straight from the vehicle, plus a price calculator that works out from current listings what a given car is actually worth today.