U0163

Code

Generic U — Network/User

Lost Communication With Navigation Control Module

Brand: Generic

Type: U — Network/User

Views: UK: 30 EN: 51 RU: 57

AI status

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Page language: EN

Causes

Navigation control module failure
Power or ground failure to the navigation module (blown fuse, poor ground)
Damaged or corroded connector pins at the navigation module
Open or short in CAN bus wiring between navigation module and other controllers
CAN bus termination resistor missing or failed
Network interference or short to battery/chassis

Symptoms

Navigation system inoperative or blank screen
Navigation voice guidance unavailable or intermittent
Related infotainment features (map, traffic, POI) not available
Instrument cluster or other modules show communication warnings or related U-codes
Stored U0163 and possibly other U0xxx network codes
Some vehicle features dependent on navigation data may not work (e.g., navigation-linked audio routing)

What to check

Connect a capable scan tool and read current and pending U-codes and freeze frame data
Verify the navigation module is present/listed on the vehicle network using a CAN network scan or module present test
Check vehicle battery voltage and charging system under key on/start conditions
Inspect fuses and fusible links for the navigation module and related bus/gateway modules
Visually inspect connectors and wiring for damage, corrosion, or loose pins at the navigation module and gateway/BCM
Measure power and ground at the navigation module connector per manufacturer pinout

Signal parameters

CAN bus idle: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (recessive state)
CAN bus dominant: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2 V)
Expected differential resistance across CAN H-L ≈ 60 Ω (two 120 Ω terminators in parallel)
Navigation module typically transmits periodic heartbeat/telemetry frames (heartbeat frequency varies by vehicle, often tens to hundreds of ms)
No valid ID/frames from the navigation module should be present when communication is lost

Diagnostic algorithm

Use a scan tool to confirm U0163 and note any related U-codes; record freeze frame and module availability.
Verify battery voltage stable (>12 V) and check relevant fuses for navigation and gateway modules; replace blown fuses and retest.
With the ignition key ON, check for presence of the navigation module on the diagnostic network (module list); if absent, inspect the navigation module connector for corrosion, bent pins, or loose terminals.
Measure power feed(s) and ground(s) at the navigation module connector per the wiring diagram; repair any lost power/ground and retest.
Check continuity of CAN H and CAN L conductors between the navigation module and gateway/BCM; repair any opens or shorts to chassis/battery.
With ignition ON, measure CAN H and CAN L voltages and bus resistance across H-L. If voltages or resistance are out of range, isolate circuit segments to find the defective node or terminator.
Use a scope or CAN analyzer to look for valid CAN frames from the navigation module and to check for bus traffic/congestion or a node in Bus-Off state; address the node causing Bus-Off.
If wiring and power/grounds are good but no communication, attempt a known-good module reflash or software reprogram per manufacturer procedures; some vehicles require module coding after replacement.
If reflash/coding not applicable or fails and the module remains unresponsive, replace the navigation control module and recheck communications.
After repair, clear codes, perform relearn/coding if required, and verify normal operation and that the U0163 does not return.

Likely causes

Blown fuse or poor battery connection supplying the navigation module
Corroded/damaged connector or pin at the navigation module or gateway module
Broken/shorted CAN H or CAN L wires (chafing, rodent damage)
Failed navigation module internal CAN transceiver
Gateway/BCM or other network node stuck in Bus-Off and isolating the navigation module
Software mismatch or failed reflash after service