U3035Communication Authentication Signal Invalid Data
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3035 means a secured message arrived but its authentication part did not check out, so the receiver treats the content as invalid. In AUTOSAR Secure Onboard Communication the receiver recomputes the message authentication code over data ID, payload and freshness value; a mismatch or an unusable key counts as failed verification and the message is dropped. Ford's SSM 51497 for 2023 Super Duty says the PCM sets U3035 when authentication fails after key initialization, harmless without other codes, MIL or drivability issues; TSB 23-2421 reflashes the 6.8L/7.3L PCM when the MIL is on with P061B, U0140 and U3035/U3036. Audi's TSB 2077740 ties U303500 with U029400 and U012900 to Q6 e-tron that cannot select a gear in cold weather. Ford TRON module replacement without new keys also causes it.
- What you may notice
- Code found during a self-test without complaints
- MIL with further network or processor codes on some engines
- Function refused, e.g. gear selection not possible in the cold
- Likely causes
- LikelyModule software rejecting valid messages, fixed by update
- PossibleKeys not aligned after a module replacement
- PossibleMessages checked before key initialization or wake-up finished
- RareCorrupted frames from wiring or bus faults
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €0 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.