What it means
A receiving module detected implausible data from the V2X (vehicle-to-everything) communication module. Position, V2V/V2I message content or signal-quality flags fail plausibility checks and are rejected.
How it works
The V2X module handles vehicle-to-everything communications, exchanging information with other vehicles or roadside systems where equipped. U042A is set when a receiving module rejects data from that V2X module as implausible, possibly because of an internal fault, a software mismatch, or gateway routing trouble.
Common causes
Most likely first.
- Module internal fault or sensor input drift
- Software version mismatch after replacement
- Gateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules and review freeze-frame data to identify which controller rejected the V2X data and whether gateway or network faults are also stored.
- Check which V2X-dependent features, if fitted, are unavailable or behaving unexpectedly, and note whether the issue began after a module replacement or software update.
- Inspect V2X and gateway connectors and visible network wiring for damage, corrosion, loose connections, or water intrusion.
- Check the V2X module's reported status and communication faults with a capable scan tool, comparing data across modules where available.
- Verify software compatibility and CAN message routing using the manufacturer's service information before replacing the V2X module.
Common fixes
- Repair a loose, corroded, or damaged V2X or gateway connection.
- Update or configure replacement-module software to the vehicle's specified compatible version.
- Correct gateway routing or a CAN network fault if testing confirms it.
- Replace the V2X module if its data remains invalid after software and network checks.
Can I keep driving?
If the vehicle drives normally, U042A usually affects V2X-dependent functions rather than basic driving; do not rely on those functions until the fault is resolved. If other warnings or control-system problems appear, stop safely and investigate before continuing.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.