U0444 Moderate Generic / SAE

U0444: Invalid Data Received From Body Control Module C

Network and Communication Invalid Data Received

What to do

Expect a group of electrical items in one part of the car to have stopped working.

If the affected things are in a door — window, mirror, lock, speaker — there is one check worth doing before anything else, and it costs nothing. Watch whether the fault changes as the door is opened and closed. If it does, the problem is a broken wire in the rubber concertina between the door and the body, which flexes every single time the door is used and eventually breaks inside insulation that still looks perfect. That is a repair to a few centimetres of wire, not a new module.

Also worth mentioning: any water you have found. Door drain holes block with grit, the door fills, and the electronics inside sit in it. A wet footwell or a sloshing noise from a door is a real clue.

The car is usually safe to drive. Check that indicators, brake lights and headlights are all working before travelling at night.

What this code means

A body control module is broadcasting data that cannot be accepted as true. See U0443 for why these modules are lettered and what that implies about where to look.

Where the zone in question is a door, one cause dominates everything else, and it is the same one the whole U02xx block turns on. The wiring between the body and a door passes through a flexible rubber boot, and that boot is flexed every time the door is opened — tens of thousands of times over the vehicle's life. Copper work-hardens and eventually breaks inside insulation that still looks perfect.

The signature is free to check and nobody thinks to try it: the fault changes as the door is moved. A code that comes and goes, or symptoms that appear only with the door in a particular position, is a broken conductor in the boot rather than a failed module.

The second cause is water, and it arrives the same way in every case. A door's drain holes clog with road grit; the door fills instead of draining; the module inside sits in it.

Otherwise this is the general case set out at U0443 — a module reporting something the rest of the vehicle cannot accept, most often because of what is feeding it rather than the module itself.

Likely causes

Start here

Broken wire in the door harness boot · moderate
Blocked door drain letting water into the module · moderate
Corroded or loose connector · easy
Water ingress into module · moderate

Less common

Damaged data bus wiring · moderate
Faulty body control module · 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

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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.