U0443 Moderate Generic / SAE

U0443: Invalid Data Received From Body Control Module B

Network and Communication Invalid Data Received

What to do

Expect a group of electrical things to have stopped working, and probably several warning lights.

The single most useful thing to notice is whether the faults are all in the same part of the car. Modern vehicles split body electrics between several computers, each looking after one area — the dash, the back, the roof, sometimes each door. So when everything at the back stops working at once, or everything in one door does, that is one module rather than five separate faults, and it is worth saying to whoever looks at it.

The car is normally still safe to drive, but check the obvious safety items yourself: brake lights, indicators, headlights and wipers. If any of those are affected, it needs attention before a night journey.

Mention any water you have found inside the car — a damp footwell, a wet boot floor, condensation inside a light cluster. These modules sit close to where water gets in, and a leak is a far commoner cause than a failed module.

What this code means

A body control module is broadcasting data that cannot be accepted as true. See U0400 for the family's framing and U0422 for what the body module does.

This code and the three after it exist because the body module is no longer one box, and understanding why is what tells you where to look.

Running a wire from a single central module to every lamp, motor, switch and heater in the vehicle is heavy, expensive and awkward to build. So manufacturers distribute the job: a module in the dash, one at the rear, one in the roof, sometimes one per door. Each sits near the things it operates and reports over the bus, so the wiring stays short.

The practical consequence is that a lettered body module is a zone, and roughly where it lives determines how it fails. A rear module sits near the tailgate seal and the light clusters, which is where water gets in. A front module sits in the dash above the footwell, which is where a blocked bulkhead drain or a leaking heater matrix ends up. A roof module sits between the sunroof drains.

And it explains the symptom pattern, which is the most useful thing on this page. When a zone module is unhappy, the failures cluster by location rather than by function — everything at the back stops working at once, or everything in one door does. A spread of unrelated electrical faults that all happen to be in the same part of the car is one module rather than many faults, and recognising that is worth more than any test.

Which physical box carries which letter is manufacturer-specific and has to come from their documentation. The standard offers an unlettered entry at U0422, an A at U0431 and B through E here, and manufacturers use them inconsistently — so do not assume B is the second-largest, or the rear one.

Likely causes

Start here

Less common

Incorrect module configuration after replacement · specialist
Faulty body control module · specialist
Damaged data bus wiring · moderate

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

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