• Check Engine Light is on
• Malfunctioning vehicle systems
• Intermittent electrical issues
• Faulty control module
• Damaged wiring or connectors
• Network communication issues
CAN: Controller Area Network, a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other.
DTC: Diagnostic Trouble Code, a code thrown by the vehicle's onboard computer to indicate a malfunction.
• U0100
• U0121
This code means that one of the car's computers isn't talking to another computer like it should. It's like when two friends stop talking to each other because of a bad phone connection.
The U0666 code indicates a loss of communication with a specific control module in the vehicle's network.
U0666 is a diagnostic trouble code (DTC) that signifies a communication error between the vehicle's control modules over the Controller Area Network (CAN) bus. This can occur if a module fails to send or receive data as expected.
• Check for other related codes
• Inspect wiring and connectors for damage
• Test the suspect control module for proper operation
• Repair or replace damaged wiring
• Replace faulty control module
• Update module software if needed
• OBD-II scanner
• Multimeter
• Wiring diagram
$150 - $600
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regular vehicle maintenance
• Inspect wiring for wear
• Ensure software updates are applied
Network Communication Issue
• Ensure all electrical connections are secure
• Consult a professional if the issue persists
Check with your vehicle manufacturer for warranty coverage on electronic components.
U0666 has been associated with network communication issues since the implementation of CAN bus systems in vehicles.
Moderate – It should be addressed soon to prevent further issues.
Driving with this code may affect vehicle safety systems. It is advisable to address the issue promptly.
• Vehicle in ignition on position
• All modules powered
The affected control module is typically located in the engine bay or behind the dashboard.
Q: What does U0666 mean?
A: U0666 indicates a communication problem between vehicle control modules.
Q: Can I drive with a U0666 code?
A: It's possible, but not recommended as it may affect vehicle performance and safety.
