OBD-II code · Network

U0408 Invalid Data Received from Vehicle Immobilizer Control Module

The ECU receives an authorisation message from the immobilizer that does not match the expected rolling code. Engine start is blocked.

Is it safe to drive with U0408?

Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.

Common causes

  • Most likelyKey not properly learned
  • PossibleSoftware version mismatch
  • Less likelyGateway 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

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
0.3–3 h
Emissions test
Usually unaffected
Parts involved
Immobilizer Module, Ecm

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.