U105400 on Seat: Information Electronics Control Module 1 No communication
Diagnostic trouble code U105400 on Seat vehicles — what it means, the common
causes, and how to confirm the real fault before replacing parts.
What does U105400 mean?
U105400 indicates: Information Electronics Control Module 1 No communication.
This relates to the Network / communication system.
Common causes of U105400
Interruption of the fiber-optic cable (ring break)
Faulty voltage supply of the transmitter or receiver control module
Faulty transmitter or receiver control module
What to check (live data)
Ring break diagnosis wire voltage signal (12V signal applied to earth for 10 seconds during ring break diagnosis test cycle)
Parts often involved in U105400
Fiber-optic cable
Data Bus On Board Diagnostic Interface J533
Ring break diagnosis wire
Don't replace parts until the root cause is confirmed — many of these codes are caused by wiring, a connector or an upstream fault, not the part itself.
Get the confirmed root cause for U105400 — on YOUR vehicle
A code is a symptom, not a diagnosis. AutoDX Pro cross-checks several
independent assessments, pinpoints the actual root cause, gives you the
exact tests to confirm it, and shows the parts — only after the cause is
confirmed. Reads your scan-tool photo and decodes your VIN with open
recalls.
U105400 is a diagnostic trouble code: Information Electronics Control Module 1 No communication.
What are the common causes of U105400 on a Seat?
Common causes include: Interruption of the fiber-optic cable (ring break), Faulty voltage supply of the transmitter or receiver control module, Faulty transmitter or receiver control module. The exact cause depends on the vehicle — confirm it before replacing parts.
Can I keep driving a Seat with U105400?
It depends on the fault and your symptoms. Some causes are minor, others can damage components or affect safety. Get the root cause confirmed before deciding.
How do I fix U105400 on a Seat?
Confirm the actual root cause with targeted tests first, then replace only the part that's at fault. AutoDX Pro gives you the root cause, the exact tests, and the parts for U105400 on your specific Seat.