Code ESP_a039 was reported by the “Stability control and ABS (ESP)” controller in the car. The letter “a” in the middle places it among entries of the alert type.
The electronic stability program — ESP, ABS, traction control and brake force distribution. These codes show up as warning lights and some assistance systems dropping out. The car still brakes, just without electronic help.
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.
Short circuit of the WSS_FR sensor line to GND or line interruption (sensor or supply line).
Invalid Data Received From Pedal Monitor: Data Length Code, Checksum or Parity invalid
Internal electronic fault detected on outlet valves.
The unit has detected an internal fault in the outlet valves
This error will be set if 2 rotation directions of the sensor signal are in one direction, the other 2 rotations are in the other direction OR 2 rotation directions of the sensor signal have no rotation, 1 rotation in one direction, 1 rotation in other direction
Check proper mounting of all four WSS. Monitor clears when all wheel speed sensors show the same rotation for 20 seconds.
Voltage at ESP supply pins exceeds specifications
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.