Fault-code directory · BCM and body-electronics assessment
A BCM can communicate with a diagnostic tool while another controller reports that its data is not usable. That distinction matters when considering a replacement body module. Communication being present does not establish that every message or input is correct.
Codes covered
U0422
U0422 concerns data received from the body control module. It is different from a lost-communication report. The controller storing the fault is describing information it received, so the sender, the receiving controller and the underlying input all need to be considered.
Confirm the full description, suffix and reporting module for your vehicle. These are diagnostic starting points, not a parts replacement list.
Evidence that helps narrow the fault
- Identify which controller stores U0422 and scan the BCM itself. Keep both reports, including any input, configuration or voltage faults.
- Record the functions affected and recent work. A replacement BCM, changed configuration, an accessory installation or a supply disturbance can change the direction of the investigation.
- Compare the relevant live inputs and module configuration with the actual vehicle equipment. Do not assume that every body function is routed through the same controller.
Choosing the next repair step
The repair decision should explain why the data is invalid. A sensor or switch supplying the BCM may be wrong, the configuration may not match, or an electronic fault may be present. Simply replacing the receiving controller because it stores the code can miss the source of the problem. Preserve original module data before any supported replacement or recovery work.
Does this apply equally to every module called BCM, BSI, FRM or SAM?
No. Those names describe different manufacturer architectures. Match the code, vehicle and fitted module to the appropriate information rather than treating the names as interchangeable parts.
Talk through the fault with AXION
Send the make, model, year, full scan report and a short description of when the fault happens. Include recent repairs or programming attempts. If you do not have a scan, describe the symptoms in your own words.
Workshop assessments are arranged by appointment in Didcot, Oxfordshire. UK-wide postal module testing and remote support are available for suitable work after compatibility and scope are agreed. Please contact us before removing or posting a module.
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Related reading
Reference for generic code terminology: Snap-on diagnostic code reference. Use the manufacturer’s current service information for the actual vehicle and test procedure. This article provides general diagnostic guidance and is not a report of a particular customer repair.