What it means
A control module is not receiving expected messages from the Navigation Control Module. Navigation functions may be unavailable; the code alone does not identify why communication was lost.
How it works
The navigation control module manages navigation functions and communicates with other vehicle modules over the network. U0163 is stored when a receiving module misses expected messages from the navigation control module for the required period; it does not by itself identify whether the cause is module power, CAN wiring, or gateway routing.
Common causes
Most likely first.
- Navigation module unpowered
- CAN wiring to navigation module broken
- Gateway module routing CAN messages incorrectly
Symptoms
- Navigation functions may be unavailable
- Other communication codes
How to diagnose it
- Scan all modules and check freeze-frame or event data for other network faults recorded at the same time.
- Confirm which navigation functions are unavailable and whether the navigation control module responds to a full-module scan.
- Inspect the navigation control module's power, ground, CAN wiring, and connectors for damage, corrosion, loose contacts, or water entry.
- Test module power and ground under load against the manufacturer's specification.
- Check CAN continuity and communication at the navigation control module, then verify gateway routing using vehicle-specific wiring information.
Common fixes
- Secure or clean a loose or corroded navigation-module connector.
- Repair damaged CAN, power, or ground wiring to the navigation control module.
- Restore a failed module power or ground connection.
- Correct gateway routing or configuration if testing identifies it as the cause.
- Replace the navigation control module only after its supply and network circuits test correctly.
Can I keep driving?
A navigation fault alone usually does not prevent basic driving, but navigation and position-dependent functions may be unavailable. If other modules also report communication loss or vehicle functions are affected, arrange diagnosis promptly.
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.