U0163 – Lost communication with navigation control module missing message

Last updated: April 11, 2026

U0163 means one or more control modules stopped receiving expected messages from the navigation control module. In plain English, the vehicle may lose navigation, map, GPS, or screen functions, and other systems that share that data may act up. According to factory diagnostic conventions used across many brands, this code indicates a communication loss, not a confirmed bad navigation unit. The -87 subtype matters here. In SAE J2012DA fault byte terms, -87 points to a missing message condition. That means a module expected network data from the navigation module and did not see it, so diagnosis must confirm whether the problem comes from power, ground, wiring, connectors, or the module itself.

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U0163 Quick Answer

The U0163 code points to a network communication problem involving the navigation control module. Check whether the navigation module appears on a full network scan first, then verify its power, ground, and communication circuits before replacing anything.

What Does U0163 Mean?

U0163 is the official ISO/SAE controlled code for lost communication with navigation control module missing message. A different module set this code because it expected data from the navigation module and did not receive it. In real use, that can disable navigation functions, knock out GPS position updates, or create infotainment and driver information issues, depending on how the vehicle shares navigation data.

Technically, the reporting module monitors network traffic and expects a valid message from the navigation control module within a certain timing window defined by the vehicle network strategy. The -87 fault subtype identifies a missing message condition. That distinction matters. The code does not prove the navigation module failed. It only proves that a required message did not arrive, so you must verify module presence, power, ground, and bus integrity before you condemn hardware.

Theory of Operation

Under normal conditions, the navigation control module powers up, joins the vehicle network, and exchanges data with other modules over a communication bus such as CAN or a gateway-managed network. It may provide map status, GPS position, route guidance, time data, or location information to the radio, cluster, telematics unit, HVAC head, or body controller. Other modules do not guess. They wait for scheduled messages and flag a fault when those messages stop.

U0163 sets when that message flow breaks down. The navigation module may lose battery feed, ignition feed, or ground. A loose connector can interrupt the bus lines. Corrosion can raise resistance enough to block communication. In some vehicles, a gateway module can no longer route messages from the navigation module to the rest of the network. Software faults can also stop message transmission. Because U-codes are intentionally general by SAE design, the exact network path varies by make and model. That is why a full module scan and basic electrical checks come before any module replacement.

Symptoms

U0163 symptoms usually center on lost network visibility and missing navigation-related functions.

• Scan tool issue: The navigation control module does not appear on the module list, will not respond, or drops in and out during a network scan.
• Navigation inoperative: The map screen freezes, goes blank, shows loading errors, or route guidance stops working.
• GPS location errors: Vehicle position jumps, stays fixed, or fails to update while driving.
• Infotainment faults: The radio or center display may reboot, lose menu access, or show communication error messages.
• Related module warnings: The cluster, telematics, or head unit may store additional U-codes for missing navigation data.
• Clock or location-based features affected: Systems that depend on navigation time or position data may act erratically.
• Intermittent operation: Navigation works after a key cycle, then drops out again when heat, vibration, or network load changes.

Common Causes

• Navigation control module lost power feed: A blown fuse, failed power distribution splice, or ignition feed loss can shut the navigation module down so other modules stop receiving its expected network message.
• High-resistance or open ground at the navigation module: A weak ground can let the module power up erratically, then drop offline under load and trigger a missing-message communication fault.
• Corroded or loose navigation module connector: Terminal spread, moisture, or oxidation at the module connector can interrupt power, ground, or CAN communication and make the module disappear from the network scan.
• Open CAN bus wiring to the navigation module: A break in CAN high or CAN low between the module and the network backbone prevents message exchange, so another controller logs U0163 when the expected message never arrives.
• Shorted CAN circuit or bus bias fault: A short to ground, short to voltage, or internal network fault can pull CAN voltage away from its normal bias and block communication with the navigation control module.
• Water intrusion in dash, console, or trunk electronics area: Water often reaches infotainment and navigation components, then causes connector corrosion or module wake-up problems that create intermittent or hard U0163 symptoms.
• Navigation module internal failure: Internal logic, power supply, or transceiver faults inside the module can stop it from transmitting even when external power, ground, and bus circuits test correctly.
• Network configuration or software mismatch: After module replacement, battery events, or programming issues, the vehicle may not recognize the navigation module correctly and other controllers may flag it as missing.

Diagnosis Steps

You need a capable scan tool with full network topology or module scan, a wiring diagram, and a digital multimeter. A lab scope helps with intermittent CAN faults. Record freeze frame data first. For U0163, focus on ignition state, battery voltage, vehicle speed, and all related communication DTCs. Freeze frame shows when the code set. A scan tool snapshot helps catch an intermittent dropout during a road test.

1. Confirm U0163 with a full vehicle scan. Record whether the code is pending, confirmed, or history. Note every related U-code, radio, infotainment, gateway, or battery voltage code. Review freeze frame for ignition state, system voltage, and vehicle speed. If U0163 stays pending only, suspect an intermittent dropout. If it returns immediately at key-on, suspect a hard power, ground, or network fault.
2. Run a network scan before touching wiring. Check whether the navigation control module appears on the scan tool list and whether it communicates directly. Then inspect the module’s fuse supply path and related power distribution. A missing module on the network scan points you toward power, ground, connector, or CAN issues before you condemn the module.
3. Check every fuse that feeds the navigation system, infotainment system, gateway, and any shared network power source. Do not stop at visual fuse checks. Verify that the fuse has battery voltage on the correct side with the circuit powered. If a feed is dead, trace that loss back through the junction block or splice before moving deeper.
4. Verify navigation module power and ground under load at the module connector. Backprobe the power feed with the circuit operating. Then voltage-drop test the ground while the module is connected and awake. Keep ground drop below 0.1 volt. Do not trust unloaded voltage or continuity alone. High resistance can pass a simple continuity test and still knock the module offline.
5. Inspect the navigation module connector and harness closely. Look for bent pins, terminal spread, water tracks, aftermarket splices, pin drag problems, and harness damage where the loom crosses brackets or trim panels. Many U0163 repairs come from fixing a poor connection at the module, not replacing the module itself.
6. With ignition ON, measure CAN circuit bias at an accessible connector. On a healthy high-speed CAN network, CAN high and CAN low both sit near 2.5 volts to ground at rest. Ignition-off voltage readings do not count because the network bias is not powered then. A reading pulled hard high, hard low, or missing on one circuit points to a short or open.
7. Turn ignition OFF and disconnect the battery before resistance checks. Measure resistance between CAN+ and CAN- at an accessible module connector or DLC path if the circuit layout allows it. A healthy terminated bus reads about 60 ohms. Around 120 ohms or OL often indicates an open path or one missing terminator. Very low resistance suggests a shorted network.
8. If the network values look wrong, isolate the faulted branch. Unplug the navigation module and compare bus resistance and bias again. If the network recovers with the module disconnected, the module or its immediate branch may be loading the bus. If the network stays faulty, move upstream toward the splice pack, gateway, or backbone and repeat the test logically.
9. If the navigation module appears on the network scan and power, ground, and CAN tests pass, verify whether the issue is a missing message from the module or a receiving-side problem. Check which controller set U0163. Then look for software, configuration, or gateway faults that block message routing even though the navigation module itself communicates.
10. After repairs, clear all DTCs and run another full network scan. Confirm that the navigation module communicates normally and that U0163 does not reset on key-on or during a road test. Use a scan tool snapshot if the fault was intermittent. Compare post-repair results to the original freeze frame and confirm all related communication codes stay gone.

Professional tip: U0163 often shows up as a secondary code when system voltage drops or another network fault takes down several modules at once. If you see multiple U-codes, do not chase the navigation module first. Find the common loss. Start with battery voltage, gateway communication, shared grounds, and splice packs. That approach prevents expensive and unnecessary module replacement.

Possible Fixes

• Restore the navigation module power feed: Repair the open fuse supply, damaged feed wire, poor splice, or ignition power source that prevents the module from powering up.
• Repair the ground circuit: Clean and tighten the ground point or repair the high-resistance ground wire after voltage-drop testing confirms excessive loss under load.
• Repair connector or terminal damage: Replace corroded terminals, correct terminal tension, remove water contamination, and secure the connector so the module maintains stable power and network contact.
• Repair the CAN branch or backbone wiring: Fix opens, shorts, or rubbed-through wiring in CAN high or CAN low, then verify proper 60-ohm network resistance and correct ignition-on bias voltage.
• Correct configuration or software issues: Program, code, or initialize the navigation module or gateway when the hardware tests good but the vehicle does not recognize the module correctly.
• Replace the navigation control module only after circuit verification: Install a known-good or new module only when power, ground, connector integrity, network wiring, and configuration all pass testing and the module still fails to communicate.

Can I Still Drive With U0163?

You can usually still drive with U0163 if the vehicle runs normally, but you should not ignore it. This U0163 code means another module stopped receiving the expected message from the navigation control module. In many vehicles, that causes a loss of navigation, map display, voice guidance, clock sync, or infotainment integration. On some platforms, the navigation module also shares vehicle speed, GPS position, or gateway data with other systems. That can affect backup camera overlays, route guidance, telematics, or certain driver-information functions. The engine and transmission often remain usable, but the risk changes by make and model. If the scan tool cannot talk to multiple modules, or if you also have battery, CAN bus, or gateway codes, limit driving until you test the network. A communication fault can spread if low voltage, water intrusion, or bus wiring damage affects more than one module.

How Serious Is This Code?

U0163 ranges from moderate inconvenience to a more important network fault. By itself, it often points to a lost communication problem in the infotainment or navigation side of the vehicle. That usually means reduced convenience, not immediate engine damage. The seriousness increases fast when the navigation control module sits on a shared communication path or acts as part of a gateway strategy. Then one failed message source, a shorted module, or a damaged connector can disturb other modules on the same network. If the vehicle shows multiple U-codes, dead scan tool communication, battery drain, repeated fuse failure, or intermittent no-start behavior, treat the problem as serious. Ignoring it can turn a simple power, ground, or connector repair into a broader network outage. Diagnose it soon, especially after water leaks, collision work, radio installation, or battery replacement.

Common Misdiagnoses

Technicians often replace the navigation control module first, and that wastes money. U0163 does not prove the module failed. It only proves another controller missed the expected message. A blown module fuse, weak ground, low system voltage, corroded connector, aftermarket radio wiring problem, or a CAN circuit fault can create the same code. Another common mistake is checking only for battery voltage at the module connector with no load applied. A weak power or ground can pass a quick meter check and still drop out under operation. Shops also miss pending and history network codes in other modules, which often show whether the fault started with a gateway, infotainment hub, or power supply issue. The right path starts with a full network scan, module presence check, and loaded power and ground testing before any replacement decision.

Most Likely Fix

The most common U0163 repair direction is restoring stable power, ground, or network integrity at the navigation control module, not replacing parts on guesswork. . On some vehicles, an aftermarket radio or prior interior repair creates the fault by disturbing the factory network. If testing proves the module has correct power, clean grounds, proper network bias, and the scan tool still cannot establish communication, then module replacement or programming becomes a valid next step. After repair, confirm the fix by performing a full network scan, clearing codes, and driving long enough for the vehicle to run its communication checks. Enable criteria vary, so follow service information for that platform.

Repair Costs

Network and communication fault repairs vary by root cause — wiring/connectors are often the source, but module-level repairs or replacements can be significantly more expensive.