What it means
A control module has stopped receiving expected messages from gateway B. Communication with modules or networks routed through that gateway may be affected.
How it works
Gateway B passes messages between vehicle networks, allowing modules on those networks to share information. This code sets when a module no longer receives expected messages from Gateway B, which can happen if the gateway loses power or ground, network wiring is damaged, or system voltage drops too low.
Common causes
Most likely first.
- Gateway B power or ground fault
- Damaged network wiring or connector
- Gateway B failure
- Low system voltage
Symptoms
- Multiple communication codes
- Some vehicle functions may be unavailable
- Warning lights or messages
How to diagnose it
- Scan all modules and review freeze-frame data to identify which modules lost Gateway B communication and when the fault occurred.
- Check battery condition and charging-system operation to rule out low voltage as a cause of multiple modules dropping offline.
- Use the network layout in service information to check which modules or vehicle functions depend on Gateway B and whether the loss is limited to a particular network.
- Inspect Gateway B connectors, power and ground connections, and accessible bus wiring for loose terminals, corrosion, water entry, or damage.
- Test Gateway B power and ground under load and check its network connections for opens, shorts, or poor connections using the manufacturer's specifications.
- If its power, ground, and network wiring pass, follow the manufacturer's procedure to assess Gateway B before replacing or configuring it.
Common fixes
- Charge or replace a weak battery and correct any charging-system fault.
- Clean and secure Gateway B connectors or repair damaged terminals.
- Repair Gateway B power or ground connections that fail testing.
- Repair an open, short, or poor connection on the network routed through Gateway B.
- Replace or configure Gateway B only after testing confirms the gateway is faulty.
Can I keep driving?
A Gateway B communication fault may affect several systems that depend on messages it routes. Drive only if essential functions work normally, and do not continue if starting, braking, lighting, or another safety-related function is impaired.
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.