U0448Invalid Data Received From Serial Data Gateway Module B
- Generic OBD-II code · Network
- How the car detects it
- U0448 concerns serial data gateway module B, a second gateway that some architectures add next to the central unit to bridge further networks; U0147 is lost contact with it. A receiver stores U0448 when B's frames arrive but alive counter, checksum or message authentication do not match. No manufacturer documents U0448 publicly. For gateway A, GM's 2025 tables show what such checks look like: a few failed samples within a short window, MIL treatment that varies by receiver, and assistance functions such as adaptive cruise switched off as a fallback. Audi's Q4 e-tron bulletin shows a faulty gateway leaving several modules reporting it at the same time. Because every message routed through B is affected, symptoms tend to appear on several systems together; software level and supply of module B come first in diagnosis.
- What you may notice
- Warnings from several systems at the same time
- Assistance or comfort functions on the networks behind gateway B unavailable
- Likely causes
- PossibleSoftware level of gateway B not matching the other modules
- PossibleSupply or ground fault at gateway B
- RareInternal fault in gateway module B
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.