What it means
A receiving module detected implausible data from the EVAP leak detection module. Tank-pressure or vacuum values fail plausibility checks and are rejected.
At a glance
- Usually lights the warning light of the system that lost communication
- Affects emissions; the car can fail an emissions test
How it works
The evaporative-emissions leak detection control module monitors fuel-system pressure or vacuum as part of checking for fuel-vapour leaks. U05A0 is set when another module rejects the leak detector's reported pressure or vacuum data as implausible; it does not identify a specific leak.
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 save freeze-frame data to see which module logged U05A0 and whether EVAP or network codes are also present.
- Review available live data from the leak detection module, including tank-pressure or vacuum readings and status, for missing or implausible values.
- Inspect the module's accessible connector and harness for loose terminals, corrosion, moisture, or damage.
- Check its power, ground, and communication wiring using the manufacturer's procedure before assuming the pressure-sensing hardware has failed.
- If the module or gateway was recently replaced or updated, verify software compatibility and vehicle configuration.
- If the data remains invalid with sound wiring, perform the manufacturer's EVAP leak-detection and module checks to isolate a module fault from a pressure-sensor or system issue.
Common fixes
- Repair damaged wiring or clean and secure the leak detection module connector.
- Correct a module power, ground, or network fault.
- Update or configure a replaced module or gateway to the vehicle's required software.
- Replace the leak detection control module if its reported pressure or vacuum data remains implausible after circuit checks.
Can I keep driving?
If the vehicle runs normally, short trips are generally possible, but arrange diagnosis because the EVAP system may not monitor fuel vapours correctly and emissions readiness can be affected. Stop if fuel is leaking or you smell strong fuel vapours.
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.