What it means
A control module has stopped receiving expected messages from gateway A. Communication with modules or networks routed through that gateway may be affected.
How it works
Gateway A routes messages between vehicle networks so modules on different networks can exchange information. This code sets when another module stops receiving expected messages from Gateway A, potentially because the gateway loses power or ground, its network connection is faulty, or system voltage is low.
Common causes
Most likely first.
- Gateway A power or ground fault
- Damaged network wiring or connector
- Gateway A 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 find which modules lost communication with Gateway A and whether they belong to one or more networks.
- Check battery condition and charging-system operation, since low voltage can interrupt the gateway and create widespread communication faults.
- Check whether modules on networks routed through Gateway A are reachable, and note whether failures are limited to one side of the gateway.
- Inspect Gateway A connectors, power and ground connections, and accessible network wiring for corrosion, looseness, water entry, or damage.
- Using the vehicle's network diagram, test Gateway A power and ground under load and check the relevant network circuits for opens, shorts, or poor connections against the manufacturer's specification.
- If the supplies and wiring are sound, follow the manufacturer's diagnostic procedure to assess Gateway A before considering replacement or configuration.
Common fixes
- Charge or replace a weak battery and repair charging-system issues.
- Reconnect or clean Gateway A connectors and repair damaged terminals or wiring.
- Repair a Gateway A power or ground fault confirmed by testing.
- Repair an open, short, or poor connection in a network circuit routed through Gateway A.
- Replace or configure Gateway A only if diagnosis confirms failure.
Can I keep driving?
Several vehicle functions may be affected if Gateway A is not routing messages, even when the engine runs normally. Check that starting, lighting, braking, and other essential systems work before driving, and avoid driving if a safety-related function is unavailable.
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.