U0289: Lost Communication With DC/AC Converter Control Module B
What to do
Expect reduced power, and expect the car to be more limited than usual.
A second inverter on a hybrid or electric vehicle usually drives a second motor. If your car has motors on both axles, it will probably still drive on the remaining one — that redundancy is designed in — but a four-wheel-drive vehicle running on one axle does not handle the way you are used to. Take extra care in the wet, in snow, and anywhere traction matters.
If your hybrid's battery has stopped charging while the engine runs, that is likely the same fault, and it will end with the battery flat and no electric assistance at all. Worth getting seen promptly.
Do not investigate anything orange. Orange cabling marks the high-voltage system, and those voltages are lethal. Take the vehicle to somebody trained and equipped for high-voltage work — this is one of the few faults where the right advice is to leave it entirely alone.
What this code means
The second DC to AC converter control module has stopped being heard from. See U0288 for what these converters do and the high-voltage caution, which applies here without modification.
A second inverter almost always means propulsion rather than accessories, and that narrows the picture usefully. Vehicles carry more than one traction inverter when they have more than one drive motor — a second motor on the other axle for four-wheel drive, or a separate generator and motor arrangement in a hybrid transmission.
The consequence follows from the architecture, and it is worth predicting: on a vehicle with independent motors front and rear, losing one inverter usually leaves the vehicle drivable on the other axle. That is a designed-in redundancy rather than a lucky escape, and it is why this code is marked drivable — but a four-wheel-drive vehicle running on one axle handles differently from the one the driver knows, particularly in poor conditions, and expects less of itself than the driver may.
So the practical advice is to expect reduced power, expect the vehicle to be more limited than usual, and not to assume normal traction.
On a hybrid where the second unit serves the generator side, the effect is different again: the vehicle may be unable to charge its pack from the engine, so it runs down the battery and then loses electric assistance altogether. A hybrid whose battery has stopped charging while the engine runs is that.
Everything at U0288 about high-voltage safety applies and should not be diluted. Orange cabling means voltages that kill, and this is work for somebody trained and equipped. Do not open covers, disconnect connectors or probe circuits on the high-voltage side.
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
- Blown fuse or failed supply · easy
Symptoms
Components involved
Information, not instruction
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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
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