U1664 – Communication Network Malfunction

The ODBII code U1664 indicates a communication network malfunction, meaning there is a failure in the communication between various control modules in the vehicle’s network.

The severity of ODBII code U1664 is moderate.

Common Causes For: U1663 Lost Communication with Body Control Module (BCM)”.

• Faulty wiring or connectors in the communication network.
• Malfunctioning control modules.
• Corrupted software or firmware in control modules.
• Poor ground connections.
• Interference from aftermarket devices.
• Damaged or shorted communication lines.
• Low battery voltage or power supply issues.
• Faulty or damaged sensors.

Common misdiagnosis for U1664 U1664: “Communication Network Malfunction”

• Faulty ABS module
• Defective engine control module (ECM)
• Malfunctioning body control module (BCM)
• Wiring issues or shorts in the communication lines
• Bad ground connections
• Faulty sensors or actuators
• Incorrectly programmed modules
• Battery or charging system problems

Common Troubleshooting Steps

The OBD-II code U1664 indicates a “Communication Network Malfunction.” This code typically points to issues within the vehicle’s communication network, which can affect various modules and systems. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors related to the communication network. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the CAN (Controller Area Network) bus wiring, as this is often involved in communication issues.
• Check for Short Circuits or Open Circuits: Use a multimeter to check for continuity in the communication lines. Look for any short circuits or open circuits that could disrupt communication.
• Test Modules: Identify the modules that are part of the communication network (e.g., Engine Control Module, Transmission Control Module, Body Control Module).
• Check if the affected modules are functioning properly. You may need to perform a module reset or reprogramming if necessary.
• Inspect for Interference: Look for any aftermarket devices or modifications that may interfere with the vehicle’s communication network. This includes alarms, stereo systems, or other electronic devices.
• Check Battery and Ground Connections: Ensure that the vehicle’s battery is in good condition and that all ground connections are secure. Poor power supply or grounding can lead to communication issues.
• Perform a Network Test: If available, use a scan tool that can perform a network test to check the communication between modules. This can help identify which module is not communicating properly.
• Update Software/Firmware: Check if there are any software or firmware updates available for the vehicle’s modules. Sometimes, updating the software can resolve communication issues.
• Clear Codes and Test Drive: After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code reappears.
• Consult Service Manual: Refer to the vehicle’s service manual for specific diagnostic procedures related to the U1664 code. Different manufacturers may have unique troubleshooting steps.1
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis and repair. By following these troubleshooting steps, you can systematically identify and resolve the underlying issues causing the U1664 code.