U0440

What it means

The Drive Motor Control Module is present on the data bus but the values it reports are implausible — out of range, frozen, or failing the checksum or rolling-count check. The receiving modules reject the data. Electric-drive torque control becomes unreliable. Causes include a faulty sensor feeding the module, internal computation errors, a software or calibration mismatch after a repair, or bus interference corrupting the frames.

Is it safe to drive?

This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.

Most likely causes

• Drive motor resolver/sensor drift

  high

  One of the most commonly reported causes for this code — check this first.

• Drive motor module internal fault

  medium

  A plausible cause — test and verify before replacing parts.

• Gateway module routing CAN messages incorrectly

  low

  Less common, but worth ruling out after the more likely causes.

Related help

• Full U0440 diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?