Code CP_a143 was reported by the “Charge port” controller in the car. The letter “a” in the middle places it among entries of the alert type.
The car's charge port — latch, connector lock, indicator light and proximity sensor. These codes typically appear when the connector will not lock or the car does not register that it is plugged in.
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.
The charge port detected an unsupported charging adapter
An unsupported charging adapter was detected
The charge cable and/or adapter is removed
Charging will not begin with the unsupported adapter
Unable to establish digital communications
The CP expires its attempts to establish SWCAN communications
The CP establishes SWCAN communictions or proximity state changes
Charging may not start or may be interrupted unexpectedly
An EVSE using legacy pilot has faulted
The EVSE sets pilot to the faulted state
Legacy pilot exits the faulted state or the charge cable is unplugged
The CCS EVSE detected low isolation during a charge session
Set when low isolation is detected by a CCS DC EVSE while DC charging
Cleared when EVSE reports nominal isolation, or when EVSE reports low isolation again, or when CCS comms are terminated
May result in loss of charging capability, either temporarily or completely if issue is with vehicle
Charge port door assembly broken
Door potentiometer reads greater than 90% for more than two seconds or potiometer reading wraps around
Door potentiometer reads less than 90% for more than one second and potiometer reading does not wrap around for more than four seconds
Charge port door may not actuate properly
DC pin thermistor open-circuit detected
DC pin temperature is less than the open circuit threshold for more than one second
DC pin temperature is greater than the open circuit threshold for more than one second
Latch is not in the blocking position but is expected to be, Gen 1 and 2 EU charge ports only
The latch position sensor indicates the latch is disengaged after the CP has attempted to engage the latch fully, or if the latch is expected to be blocking cable insertion
Latch enters the blocking state
Latch may not block cable insertion when expected
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.