Fault-code directory · Module programming and compatibility enquiries
A replacement controller can communicate normally yet still be unsuitable for the vehicle’s software and configuration. When a software-incompatibility code appears, pause further programming attempts until the hardware, current software and intended commissioning route have been checked.
Codes covered
U0300 · U0301 · U0302 · U0303 · U0304 · U0305 · U0308
These codes concern internal or inter-module software compatibility, including engine, transmission, transfer-case, gear-selection, cruise and throttle-control relationships. They are not proof of damaged flash memory. An incompatible donor and an incomplete programming job require different solutions.
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
- Keep original and donor part numbers, hardware and software identifiers, and the full before-and-after scans. Photograph labels clearly without publishing vehicle security information.
- Record the tool, approved software route and exact stage at which programming or coding stopped. A screenshot of the failure message is more useful than saying that coding failed.
- Confirm whether the replacement is supported and what configuration, calibration or authorisation is required. Do not repeat writes using unrelated files to see whether one works.
Choosing the next repair step
The next step may be correct commissioning, an appropriate software update, a different compatible unit or investigation of an interrupted operation. A good programming plan includes stable power support, a supported interface, preserved original information and post-programming checks. Availability depends on the actual vehicle and module.
Does matching the connector and part-number prefix guarantee compatibility?
No. Hardware revisions, software families, installed equipment and security requirements can differ. Send both full identifiers before buying a donor or booking a remote programming session.
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.
Assessment options and appointments · Garage and trade support
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.