Corroded, loose, or damaged BCM connector pins or terminals causing intermittent data corruption.; A failing BCM 'B' internal fault that produces out-of-range or malformed CAN messages.; Wiring damage in the CAN bus between the BCM and the receiving module, including chafed or shorted twisted pairs.; Low or unstable battery voltage causing the BCM to reset or transmit invalid frames.; Water intrusion into the BCM or its connectors, common when the module is mounted low in the cabin.; Aftermarket accessories tapped into the CAN bus or BCM wiring that introduce noise or invalid signals.; A software or calibration issue in the BCM or receiving module that misinterprets valid data.

DTC codes / U04xx · Invalid data received from a module / U0443

U0443Invalid Data Received From Body Control Module B

Q: What does code U0443 mean?

Invalid Data Received From Body Control Module B. U0443 indicates that a control module on the vehicle's controller area network (CAN) received invalid or corrupted data from the body control module (BCM) 'B'. The receiving module detected that the BCM's messages were missing expected values, out of range, or failed a checksum, so it flagged the communication as unreliable rather than treating the data as valid.

U0443 indicates that a control module on the vehicle's controller area network (CAN) received invalid or corrupted data from the body control module (BCM) 'B'. The receiving module detected that the BCM's messages were missing expected values, out of range, or failed a checksum, so it flagged the communication as unreliable rather than treating the data as valid.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaInvalid data received from a module

Symptoms you may notice

Often no symptoms besides the warning light, because the fault may be intermittent or affect only non-critical body functions.
Intermittent or completely inoperative interior accessories such as dome lights, power windows, or door locks.
False warnings or erratic operation of the security system, keyless entry, or remote start.
Battery drain if the BCM remains awake and keeps broadcasting invalid data on the network.
Other modules may set communication codes or enter default modes when BCM data is rejected.
Warning chimes, turn signals, or wipers behaving unpredictably if the BCM shares those functions.

Common causes, most likely first

Corroded, loose, or damaged BCM connector pins or terminals causing intermittent data corruption.
A failing BCM 'B' internal fault that produces out-of-range or malformed CAN messages.
Wiring damage in the CAN bus between the BCM and the receiving module, including chafed or shorted twisted pairs.
Low or unstable battery voltage causing the BCM to reset or transmit invalid frames.
Water intrusion into the BCM or its connectors, common when the module is mounted low in the cabin.
Aftermarket accessories tapped into the CAN bus or BCM wiring that introduce noise or invalid signals.
A software or calibration issue in the BCM or receiving module that misinterprets valid data.

How to diagnose and fix it

Verify battery state of charge and charging system output, then clear the code and test-drive to see if it returns.
Inspect the BCM connectors and terminals for corrosion, water intrusion, and loose pins, cleaning or repairing as needed.
Check CAN bus wiring between the BCM and the module that stored U0443 for continuity, shorts, and chafing.
Disconnect aftermarket accessories wired into the BCM or CAN bus and retest to rule out signal interference.
Use a scan tool to monitor live BCM data and confirm whether the invalid data is continuous or intermittent.
Perform a wiggle test on BCM harnesses and connectors while watching live data to expose intermittent faults.
If wiring and power are confirmed good, replace or reprogram the BCM 'B' and verify communication with all modules.

What U0443 does not always mean

U0443 does not automatically mean the BCM is bad; a loose ground or low battery voltage can corrupt CAN messages and set this code without any module failure.
Many technicians replace the BCM only to find a corroded connector or chafed CAN wire was the real cause, so harness inspection must come before parts replacement.
Aftermarket alarms, remote starters, or dash cameras tapped into the CAN bus frequently introduce invalid frames that the receiving module rejects as U0443.
This code can be stored alongside U0140 or other BCM communication codes, and clearing them without fixing the underlying wiring fault will only make the code return.
On some vehicles the BCM 'B' designation refers to a second body module, so confirm the exact module location in the service information before testing.

Can I keep driving with U0443?

The vehicle is generally safe to drive because U0443 usually affects body accessories rather than engine or brake control, but avoid long trips until the cause is found. If the warning light is accompanied by erratic electrical behavior or a battery drain, have the fault diagnosed promptly to prevent a no-start condition.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.