Code GTW_w029 was reported by the “Gateway” controller in the car. The letter “w” in the middle places it among entries of the warning type.
The Gateway — the hub through which the car's controllers talk to each other, and the route software updates take. Codes from here often mean some controller has gone quiet on the bus; the real fault is usually in that controller, not the gateway.
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.
IBSTCAL is running different version than the expected
IBSTCAL may not function properly
I2C bus failed. I2C will be reset
Fatfs FAT area is corrupted. Format needed
IBST is running different version than the expected
IBST may not function properly
CP is running different version than the expected
Ethernet interface receive buffer error
A reboot for update occurred but the Updater did not run
Software update is attempted to initiate
PCS is running different version than the expected
CBC is running different version than the expected
Log queue is full or SD card having problems
May clear itself after burstiness or Format SD card
Bus failed to sleep when commanded
CMPS is running different version than the expected
Thermal system may not function properly
Setting of RTC alarm failed. GTW will remain awake
CMP is running different version than the expected
PARK is running different version than the expected
PARK may not function properly
Fault Confinement is passive or bus off.
Communication on VEH bus may fail
SD card is at its max rated program/erase cycles
SD card at its max rated program/erase cycles
SD card may enter read-only mode preventing logging, updates etc.
Exception on Gateway CPU occurred
Invalid number of tasks running
Indicates an electrical issue with the CAN bus. Note: GTW hardware hwid=1 does not support reporting of this alert
CH bus has abnormal load (>70%)
A rogue ECU or unexpected event
Some messages on CH bus may be dropped
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.