【Tutorial】Complete Solution for Communication Fault of 90CL Control Unit on FAW‑Audi A3L 2025 Model

Recently, a number of FAW‑Audi A3L vehicles equipped with the 90CL control unit have experienced stability issues with functions such as connected‑car login and emergency call activation. Typical symptoms include:

  • Failure to log in to the connected‑car account
  • Prompt: “Login incomplete, please try again later”
  • Persistent static fault codes
  • Unavailable emergency call (eCall) with indicator light off
  • Failure to establish backend communication

Root Cause of the Fault

After the certificate of the internal ConMod communication module inside the 90CL (J949) expires, the vehicle cannot establish a verified connection with remote servers over encrypted channels. This directly results in:

  • Failed IVI login for Chinese‑region accounts
  • Locked‑up emergency call function
  • Offline status displayed for relevant functional modules
  • Communication errors and backend verification‑failure DTCs visible within ODIS

This fault cannot be resolved by simple initialization or data clearing. A firmware upgrade is mandatory to replace the new certificate signature.

Please download the attachment for the full step‑by‑step tutorial.

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