OBD-II code · Network (extended)
U3035 Communication Authentication Signal Invalid Data
The received authentication signal contains invalid data — message authentication code does not match expected value, suggesting tampering or corruption.
Is it safe to drive with U3035?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyAuthentication code mismatch
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
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
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Can Bus, Security Module
Related codes
- U3032Ignition Output Accessory/Off
- U3033Control Module Security Certificate Missing/Invalid
- U3034Communication Authentication Key/Certificate Missing/Invalid
- U3036Communication Authentication Signal Performance
- U3500Control Module Input Power A Circuit Range/Performance
- U3501Control Module Input Power A Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.