What it means
A receiving module detected invalid data from Gateway B. The code does not by itself identify the source of the invalid data or establish that a gateway fault is present.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
A receiving module checks messages from Gateway B, which routes data between vehicle networks or modules. U0448 sets when the receiving module considers a Gateway B message invalid and rejects it; the code alone cannot distinguish bad source data from a gateway power, network, or internal fault.
Common causes
Most likely first.
- Invalid data from Gateway B
- Gateway power, ground, connector, or network fault
- Gateway module fault
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules and save freeze-frame data and communication codes to identify the reporting module and any faults involving Gateway B.
- Identify which vehicle functions are affected and compare their actual state with the data shown by the relevant modules.
- Inspect Gateway B’s connectors, power and ground connections, and accessible network wiring for corrosion, looseness, or physical damage.
- Compare relevant Gateway B and receiving-module live data with a scan tool to see whether the message is wrong, missing, or inconsistent.
- Check for recent gateway or module replacement, programming, or software changes that could leave configuration or versions mismatched.
- Test Gateway B’s power, grounds, and network circuits using wiring information and manufacturer’s specifications before replacing the gateway.
Common fixes
- Repair a loose, corroded, or damaged Gateway B connector or network wire.
- Repair a confirmed gateway power or ground fault.
- Correct software compatibility or module configuration after replacement or programming.
- Repair a gateway network routing or wiring fault identified by testing.
- Replace Gateway B only if its power, grounds, wiring, and software are sound and it continues to send invalid data.
Can I keep driving?
A cautious drive may be possible if the vehicle operates normally and no safety-related functions are affected. Do not continue if the fault disables essential controls, lighting, or other equipment needed to drive safely.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.