Code RADC_a044 was reported by the “Radar” controller in the car. The letter “a” in the middle places it among entries of the alert type.
The forward radar on older Autopilot cars. These codes mostly report a blocked radar — snow, ice, a sticker or road salt in front of the sensor. Newer Teslas have no radar and rely on cameras alone.
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.
A condition prevents successful CANRX (CAN message received) for the steering wheel angle message, relating to a checksum, a counter, or an out-of-bounds signal value.
The steering wheel angle message sent from the driver assistance system (DAS) Electronic Control Unit (ECU) to the radar controller (RADC) ECU is not as expected / as required for the radar to be enabled.
ECU Internal fault - Hardware Watchdog
ECU Internal fault - ADC Conversion Timeout
ECU Internal fault - Mode Control Entry Error
Vehicle Dynamics Error - the vehicle dynamics signals are out of spec, MIA or SNA
ECU Internal ADC Overvoltage - Indicates an over voltage condition for the following voltage rails 1V25, 3V3, 4V5, 5V.
Set when the voltages for the respective rails are above threshold.
Cleared when over voltages return to nominal.
Sensor function will be impaired, radar functions will be unavailable
ECU Internal fault - ECU Module Configuration Error
Received Country Does Not Match Learned Parameter
When the learned parameters meet the ones being sent to the radar on CAN.
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.