Code CP_a049 was reported by the “Charge port” controller in the car. The letter “a” in the middle places it among entries of the alert type.
The car's charge port — latch, connector lock, indicator light and proximity sensor. These codes typically appear when the connector will not lock or the car does not register that it is plugged in.
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.
Multiple charge cables detected
The CP detects both AC and DC GB charging cables
The CP detects either one or no GB charging cable
Silent alert for UHF faults during sleep
The modem successfully booted into its application, but required the CP to reset it first
Failed to establish comms with supercharger during SECC discovery
Control pilot signal from charging station is lost while charging. Charging may be interrupted.
info from manualCP_A055
Proximity is detected with no control pilot signal and no digital communications while the vehicle is charging.
Lost communication with HVLINK
Charge port does not receive all expected CAN messages from the HVLINK
Charge port receives all expected CAN messages from the HVLINK
The CP uses this for specfic exceptions triggered in code, like data exceptions or machine check errors
12V supply undervoltage, cannot charge
The CP's measured 12V supply reads less than 8V
The CP's measured 12V supply reads above 8V
Proximity circuit was opened unexpectedly while charging. Charging may be interrupted.
info from manualCP_A056
The charge port (CP) detects that there is no charge cable present while the vehicle is charging.
Any charge port (CP) door sensor detects that the door is closed.
Door hall effect sensor is out of range (Gen 1 EU only)
Door hall effect sensor reading is out of expected range for more than five seconds
Door hall effect sensor reading is within expected range for more than one second
Inability to sense door presence
Charge port does not receive all expected CAN messages from the VCSEC
Charge port receives all expected CAN messages from the VCSEC
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.