U0448 code meaning
Invalid Data Received From Serial Data Gateway Module B
What U0448 means
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.
U0448 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0448
- Warnings from several systems at the same time
- Assistance or comfort functions on the networks behind gateway B unavailable
Common causes of U0448
- PossibleSoftware level of gateway B not matching the other modules
- PossibleSupply or ground fault at gateway B
- Less likelyInternal fault in gateway module B
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Vehicle gateway
What each part of U0448 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 48 | The exact fault in that area. |
What to do next
- Note U0448 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0448
What does U0448 mean?
U0448 means "Invalid Data Received From Serial Data Gateway Module B". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with U0448?
U0448 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0448 fail an emissions test?
U0448 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0448 to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 2.5 hours of work. This is a job for a workshop.
Will U0448 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.