Code DIF_a202 was reported by the “Drive inverter — front” controller in the car. The letter “a” in the middle places it among entries of the alert type.
The front drive unit on all-wheel-drive cars. The codes mean the same as the DI group, but refer to the front motor.
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.
Drive Inverter Warning: Ambient under temperature
Ambient temperature (refer to pcbTemp) drops below lower temperature threshold
Ambient temperature rises above lower temperature threshold
No direct impact. Could damage drive inverter if temperature is continuously too low.
Drive Inverter Warning: High gear lash angle measured
Drive Inverter Warning: Stator sensor 2 bad
Drive Inverter Warning: Stator over temperature
Stator temperature exceeds upper temperature threshold
Stator temperature drops below upper temperature threshold
No direct impact. Could damage drive unit if temperature is continuously too high.
Drive Inverter Warning: Outlet over temperature
DI coolant outlet temperature (refer to outletTemp) exceeds upper temperature threshold
DI coolant outlet temperature drops below upper temperature threshold
No direct impact. Could damage drive inverter if temperature is continuously too high.
Drive Inverter Warning: Phase A peak over current detected in hardware
Drive Inverter Warning: Phase B rms over current
Drive Inverter Warning: Heatsink over temperature
Heatsink temperature (refer to heatsinkTemp) exceeds upper temperature threshold
Heatsink temperature drops below upper temperature threshold
Drive Inverter Warning: ABS CAN node is MIA
Drive Inverter Warning: Torque limited because rotor is too hot
Drive Inverter Warning: no motor speed as encoder irrational and abs mia
Drive Inverter Warning: Loss of motor control
Motors are not responding to DI commands
Drive Inverter Warning: No Stator sensor available
All stator sensors are giving abnormal measurements
At least one stator sensor returns to rational measurements
Drive Inverter Warning: Track A Disconnected
Drive Inverter Warning: Phase B current sensor bad
Drive Inverter Warning: Track B disconnected
Drive Inverter Warning: Phase C rms over current
Drive Inverter Warning: Unit graceful power off triggered
Diagnostic alert for software trigger of mechanical three phase short
Inverter detects a shorted switch. See payload signals for information on which trigger algorithm occurs
Clears when LV power is removed from drive unit or a non-drive/drive cycle occurs
Drive unit may become permanently disabled
Drive Inverter Warning: Phase A peak over current detected in software
Drive Inverter Warning: Hardware latched fault response in an unexpected state
Measured latched fault response does NOT match with expected request from DI
Measured latched fault response matches with expected request from DI
In the event of a sudden LV loss at speed, latched fault response may not match expectations, exposing drive unit to unexpected torque
Drive Inverter Warning: Phase B current offset too big
Drive Inverter Warning: Low flow rate of fluid
Insufficient cooling to the drive inverter is detected
Cooling is sufficient and a drive cycle is executed
Drive Inverter Warning: External torque command error
Drive Inverter Warning: Phase A current sensor bad
Drive Inverter Warning: Phase A current offset too big
Drive Inverter Warning: Motor speed mismatch
Drive Inverter Warning: Outlet under temperature
DI coolant outlet temperature (refer to outletTemp) drops below lower temperature threshold
DI coolant outlet temperature rises above lower temperature threshold
Diagnostic alert for software trigger of mechanical two phase open
Drive Inverter Warning: Power stage applied a safe state
Drive Inverter Warning: Battery over voltage detected in software
HV bus voltage (refer to busVoltage) exceeds upper voltage theshold (refer to busHighLimit)
HV bus voltage drops below upper voltage threshold
Drive Inverter Warning: Battery sensor bad
When HV bus is up, DI measured bus voltage very low or disagrees with BMS reported voltage
When HV bus is up, DI measured bus voltage matches BMS reported voltage
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.