Code HVP_w043 was reported by the “High-voltage protection” controller in the car. The letter “w” in the middle places it among entries of the warning type.
The high-voltage protection unit — battery contactors, current measurement and the HVIL safety loop that disconnects high voltage the moment a connector comes loose. These codes turn up after collisions and after service work alike.
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.
Warn if pack contactors are forced open
Warns if the BMS node is mia on HVI CAN
The BMS node is mia on HVI CAN
The BMS node is not mia on HVI CAN
CAN messages are not received from BMS or other nodes on vehicle
Warns if the HVP detects unintended loss of contactor control (V or I)
The HVP detects loss of contactor power or coil current
Contactor power or coil current is dropped below threshold
The contactors opens unintentionally
Warns if the voltage and temperature readings from primary BMB chain are mia
The voltage and temperature readings from primary BMB chain are mia
The voltage and temperature readings from primary BMB chain are not mia
The secondary bmb chain is used exclusively for voltage and temperature protoection
Alerts if any of the pyro diagnostic has failed or the pyro has blown
One of many pyro diagnostic has failed including the pyro having blown
Clears after all the diagnostic has passed
Sorry, Contactors are not allowed to close.
Warn if pack contactors are not allowed to close
This meta alert will set if any of the reasons for preventing contactors to close (listed in this alert payload) are still present. This alert is always set with an accompanying alert that provides more specific information for the fault.
Pack contactor blocking condition is cleared
While this alert is set, HV contactors will not be able to close. This will prevent drive, charge and 12V support and eventually the 12V battery will be fully discharged and the vehicle will go offline.
The PCS node is mia on HVS CAN
The PCS node is not mia on HVS CAN
CAN messages are not received from PCS node
Warn if FC contactors are not allowed to close
FC contactor blocking condition is cleared
warn if shunt temerature exceeds high threshold value
shunt temperature falls below low threshold value
This is an indication that there could be a high impedance joint and prolonged time at this temp could affect the properties of the manganin
Warn if the CPIL fault is detected
Warns if the HVP detects series arc at FC contactor
The HVP detects series arc at FC contactor
The arc condition is not detected at FC contactor
Warns if the CP version mismatch
HVP cannot trust the CP indication, thus it is not safe to charge
warn if if the thermistor sense line is not connected
This is an indication that shunt thermistor is not in place/missing/bad
Warns if the crash signal is detected by HVP
The crash signal is detected by HVP
The ENS idle siganl is detected on ENS line
Warns if the low voltage battery is below minimum voltage threshold
The low voltage battery is below minimum voltage threshold
The low voltage battery is above minimum voltage threshold
The contactors may not remain closed
A brick voltage is below minimum voltage limit
A brick voltage is below minimum voltage limit for X duration (in seconds)
All brick voltages are above minimum voltage limit
The conactors may open immdediately or pyro fuse may blow
The Gateway node is mia on HVS CAN
The Gateway node is not mia on HVS CAN
CAN messages are not received from Gateway node
Warns if the pack current (discharge or charge) is above max current limit.
The pack current (discharge or charge) is above max current limit.
The pack current (discharge or charge) is below max current limit.
Warns if the pack discharge is above max discharge current limit
The pack current is above max discharge current limit for X duration (in msec)
The pack current is below max discharge current limit
The contactors will open immdediately or pyro fuse may blow
A pack module temperature is above maximum temperature limit
A pack module temperature is above maximum temperature limit for X duration (in seconds)
All pack module temperatures are below maximum temperature limit
The HVP part number may be missing, incorrect, or unsupported
The HVP is unable to initialize parameters related to PCBA configuration
Warns if the HVP detects series arc at pack contactor
The HVP detects series arc at pack contactor
The arc condition is not detected at pack contactor
A brick voltage is above maximum voltage limit
All brick voltages are below maximum voltage limit
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.