Network, generic (extended)

U3035 Communication Authentication Signal Invalid Data

Check engine lightOn

EmissionsNot relevant

Drive cycleNot required

Limp modePossible

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.

Likely causes

Module software rejecting valid messages, fixed by update

Keys not aligned after a module replacement

Messages checked before key initialization or wake-up finished

Corrupted frames from wiring or bus faults

Symptoms

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

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€0–300

Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

can bussecurity module

Related codes

U3036 U3034 U3033 P061B U0140

References: autosar.org, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.