U0163 Code Symptoms, Causes, Diagnosis, Repair Steps & Costs Guide

U0163 Communication Failure: Symptoms, Diagnosis, and Repair Steps

Drivers notice the problem almost immediately because the navigation system is the first thing that stops working. A blank or frozen map display, an intermittent GPS lock, or a persistent “Navigation System” warning on the instrument cluster are the most common alerts. Turn‑by‑turn directions may disappear, and voice prompts that rely on GPS can become silent. The fault does not affect engine performance, transmission operation, or safety‑critical systems such as airbags or ABS.

Symptoms

• Blank or frozen navigation screen – the map graphic stays static or the entire display goes dark.
• Loss of GPS signal – the vehicle no longer shows a satellite lock; the “GPS” icon disappears.
• Disabled turn‑by‑turn guidance – voice prompts and route recalculations stop working.
• Navigation‑system warning light or message – a dashboard indicator or on‑screen alert specifically mentions “Navigation System” or “GPS.”
• Intermittent infotainment glitches – occasional freezes or reboot cycles that coincide with the loss of navigation data.

Because the NCM only controls the navigation and infotainment functions, you will not notice rough idle, stalling, loss of power, or any drivability issues.

Why This Happens

Faulty Navigation Control Module Hardware

The NCM contains a processor, memory, and a GPS receiver. Internal component failure—such as cracked solder joints, moisture‑induced corrosion, or a damaged GPS antenna—prevents it from responding to CAN‑bus requests, triggering U0163.

Wiring Harness Damage or Corrosion

The NCM communicates through the vehicle’s CAN bus. Frayed wires, corroded pins, or loose connector clips break the data path. Even a single high‑resistance joint can cause the control unit to appear offline to the scan tool.

CAN‑Bus Voltage or Termination Issues

The CAN network requires a stable 2.5 V common‑mode voltage and correctly placed termination resistors (120 Ω at each end). A voltage drop below 2.2 V or an open/shorted termination can corrupt the handshake between the NCM and the body control module, resulting in lost communication.

Corrupted or Out‑of‑Date Firmware

Software bugs, incomplete updates, or memory glitches can cause the NCM to stop broadcasting its identifier. A re‑flash often restores proper operation, but if the flash fails repeatedly the module may need replacement.

Power‑Supply Anomalies (Secondary Consideration)

A weak power source—often due to a marginal fuse or a voltage regulator that is beginning to fail—can cause intermittent loss of NCM operation. While the primary focus should remain on the module and its data path, checking the supply voltage (12.0–14.5 V while the engine runs) helps rule out this secondary factor.

Diagnostic and Repair Procedures

1. Read the Code with a Manufacturer‑Specific Scan Tool

– Connect the OBD‑II interface, select the “Network” or “Communication” screen, and verify that U0163 is present.

– Note any additional codes (e.g., U0100 “Lost Communication With Vehicle Speed Sensor Module”) that may indicate a broader CAN‑bus problem.

1. Confirm NCM Presence on the CAN Bus

– In the live‑data view, locate the NCM’s module ID. If the ID does not appear, the bus cannot see the module.

1. Inspect Wiring and Connectors

– Visually examine the harness for chafing, crushed clips, or water intrusion.

– Perform a continuity test on each pin of the NCM connector (typically a 16‑ or 20‑pin plug).

– Clean corroded pins with electrical contact cleaner and a soft brush.

1. Test Power and Ground at the NCM

– Measure voltage at the power pin with the ignition on; it should read 12.0–14.5 V.

– Verify ground resistance is below 0.1 Ω.

1. Check CAN‑Bus Termination and Voltage Levels

– Using a CAN‑bus analyzer, confirm the differential voltage stays within 1.5–3.5 V.

– Verify the 120 Ω termination resistors are present at both ends of the network segment that includes the NCM.

1. Attempt a Re‑Program / Firmware Update

– If the module powers up and the bus is healthy, re‑flash the latest navigation software using the dealer’s update package.

– Re‑programming typically costs $200–$400 for labor and software, plus any required licensing fees.

1. Evaluate Repair Viability

– Minor board repairs (e.g., replacing a blown capacitor) may cost $150–$300 in labor, but success rates drop sharply after moisture damage or repeated communication loss.

1. Replace the Navigation Control Module When Needed

– Install a VIN‑matched replacement, program it to the vehicle’s specifications, and perform a post‑install verification scan.

– Replacement parts generally run $600–$900, with labor of $200–$300 for removal, installation, and final coding.

When Replacement Makes Sense

Repeated communication failures, a history of water intrusion, or an NCM that is more than eight years old usually indicate that repair will be temporary. A fresh module eliminates latent defects, and modern replacements come pre‑programmed to the vehicle’s VIN, reducing the risk of mismatched software.

Flagship One’s expertise

Modern control modules are tightly integrated with security, immobilizer, and infotainment systems. That integration makes correct programming as critical as the hardware itself. Flagship One specializes in VIN‑matched control modules, providing a plug‑and‑drive solution backed by a comprehensive warranty. Replacement units vary depending on production date and software version, so the correct module is matched by VIN before programming. This ensures seamless communication with the CAN bus and eliminates the guesswork often associated with aftermarket parts.

Preventive Maintenance

• Keep connectors dry and clean – inspect the NCM harness during routine service; spray contact cleaner if any corrosion is visible.
• Protect wiring from abrasion – route cables away from moving parts and sharp edges, especially in the dashboard area where the NCM resides.
• Schedule periodic software updates – manufacturers release navigation‑system patches that address known communication bugs.
• Monitor CAN‑bus health – a professional scan every 30 000 mi can detect early voltage or termination issues before they cause a U0163.
• Avoid aftermarket accessories that tap the CAN bus without proper shielding; poorly shielded devices can introduce noise that interferes with NCM communication.