Code OCS1P_w138 was reported by the “Passenger occupancy detection” controller in the car. The letter “w” in the middle places it among entries of the warning type.
The occupant classification system for the passenger seat. Using weight and capacitive sensing it decides whether to arm the front airbag. Codes here mean the car is unsure — and the airbag may therefore stay disabled.
The car is flagging that something is not right. Driving is usually still possible, but some function may be limited.
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 seatback self capacitance sensor reading has a low duty cycle
The sandwich sensor is disconnected
The frequency reading is > 38kHz
The frequency reading returns below 38kHz
The frequency reading is 1kHz
The frequency reading returns above 22kHz
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.