U170A00 on Volkswagen: Control module for distance regulation No communication on Ethernet data bus (Unauthorized)
Diagnostic trouble code U170A00 on Volkswagen vehicles — what it means, the common
causes, and how to confirm the real fault before replacing parts.
What does U170A00 mean?
U170A00 indicates: Control module for distance regulation No communication on Ethernet data bus (Unauthorized).
This relates to the Network / communication system.
Common causes of U170A00
Communication partner (control module for distance regulation) is not responding on Ethernet data bus
Faulty voltage supply to the control module
Faulty Ethernet cable (open circuit or damaged)
What to check (live data)
Voltage supply to the control module
Ethernet cable continuity/integrity
Parts often involved in U170A00
Ethernet cable (shielded or unshielded)
Control module for distance regulation
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 U170A00 — 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
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U170A00 is a diagnostic trouble code: Control module for distance regulation No communication on Ethernet data bus (Unauthorized).
What are the common causes of U170A00 on a Volkswagen?
Common causes include: Communication partner (control module for distance regulation) is not responding on Ethernet data bus, Faulty voltage supply to the control module, Faulty Ethernet cable (open circuit or damaged). The exact cause depends on the vehicle — confirm it before replacing parts.
Can I keep driving a Volkswagen with U170A00?
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 U170A00 on a Volkswagen?
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 U170A00 on your specific Volkswagen.