OBD-II code family
Invalid Data Received From Body Control Module (U0431–U0446)
5 codes describing the same fault on 5 enumerated slots. The letter is the index your manufacturer assigned — it is not a physical difference, and it does not carry across makes.
Codes in this family
All 5 codes below share this diagnosis. Each one has its own page with the specific causes, symptoms and repair costs for that slot.
- U0431Body Control Module “A”Invalid Data Received From Body Control Module 'A'
- U0443Body Control Module “B”Invalid Data Received From Body Control Module 'B'
- U0444Body Control Module “C”Invalid Data Received From Body Control Module 'C'
- U0445Body Control Module “D”Invalid Data Received From Body Control Module 'D'
- U0446Body Control Module “E”Invalid Data Received From Body Control Module 'E'
What these codes mean
The distinction that runs through this family is between a module that has gone quiet and one that is talking nonsense. These codes are the second kind: the body control module is present on the network and communicating normally, but a value it sent was rejected as implausible by the module receiving it.
That rules out most of what you would check for a communication dropout. The bus is working. The module has power. What is wrong is the content of a specific message, which means the useful question is not "why is it silent" but "which value did it get wrong, and where did that value come from?" A body control module reports things it reads from elsewhere — switch positions, door and latch states, lighting requests, ambient light and temperature inputs. An implausible message frequently starts at one of those inputs rather than inside the module.
The letter A through E indexes which body control module on vehicles fitted with more than one, and has no generic meaning across manufacturers.
Three causes account for most of these codes. A failed or stuck input — a door latch switch that reports open and closed simultaneously is a classic, because it makes the module send a state that cannot physically exist. A software mismatch after a module was replaced or updated without the rest of the vehicle being brought in step. And low system voltage, which corrupts data in ways that look exactly like a logic fault; check the battery and charging system before anything else, because it is the single most common cause of spurious invalid-data codes across every module on every vehicle.
Which body control module is mine?
There is no generic answer, and any source that gives you one is guessing. The letter is assigned by the vehicle manufacturer, and the same letter refers to different physical components on different makes — sometimes on different model years of the same vehicle. The only authoritative source is the wiring diagram or service information for your exact year, make, model and body style.
Where the manufacturer publishes its own meaning for this code, that is the one to work from — it describes the actual component on your vehicle, which the generic definition cannot. Keep the generic description for what it is good for: it tells you which subject area the standard assigned the code to, which is useful context when the two appear to disagree. If they do disagree, follow the manufacturer.