U0292: Lost Communication With Drive Motor Control Module B
What to do
Expect much less power, and expect the car to handle differently. Your vehicle has motors on both axles; one has dropped out, so it is now driven by one end only. A car that was four-wheel drive and is suddenly not behaves differently in the wet, in snow, and under acceleration. Take real care.
Expect the braking to feel different too. A lot of the slowing you are used to comes from the motors rather than the brake pads, and with one motor gone there is less of it. If you normally drive with one pedal, the car will now coast further than you expect — leave more room and get used to it deliberately rather than finding out at a junction.
Drive gently and get it looked at rather than continuing a long journey.
Do not investigate this yourself, and do not touch anything with orange cabling. Orange marks the high-voltage system, and those voltages are lethal on contact. This needs somebody trained and equipped for high-voltage work.
What this code means
The second drive motor control module has stopped being heard from. See U0200 for the block's framing and U0289 for the high-voltage caution, which applies here in full.
A second drive motor control module means a second traction motor, and on the vehicles that have one — dual-motor electric cars, hybrids with motors on both axles, and some performance vehicles with a motor per wheel — that motor is doing a substantial share of the driving.
Losing it produces a vehicle that still moves and is markedly different, and both halves of that sentence matter.
It still moves because the remaining motor can drive the vehicle, which is a deliberate design property rather than luck.
It is different in ways worth anticipating. Power is sharply reduced. A dual-motor vehicle running on one axle has fundamentally changed its driven-wheel layout — a car that was four-wheel drive is now front- or rear-driven only, which changes how it behaves in the wet, in snow and under hard acceleration. And regenerative braking through the lost motor is gone, so the pedal feel and the amount of deceleration on lifting off will both change. On a vehicle where one-pedal driving is normal, that is a change to how the car slows down, and it is worth adapting to deliberately rather than discovering at a junction.
So the advice is: expect less power, expect different handling, and expect the brakes to behave differently. Drive it gently and get it seen.
The high-voltage warning is not boilerplate here. Traction motors and their inverters operate at voltages that are lethal on contact, and the cabling is orange to say so. Do not open covers, disconnect anything orange, or probe these circuits. This is work for somebody trained and equipped, and it is one of the few places where the right answer is to leave it entirely alone.
Likely causes
Start here
- Corroded or loose connector · easy
- Damaged data bus wiring · moderate
- Failed power or earth supply to the module · moderate
Less common
- Water ingress into module · moderate
- Another module holding the bus down · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about U0292.