🔧 FixIt

U0120: Lost Communication With Starter / Generator Control Module

What Does U0120 Mean?

U0120 is a diagnostic trouble code indicating: Lost Communication With Starter / Generator Control Module. This code relates to the network communication system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

What To Do Next

  1. 1
    Find your vehicle above

    Click your make and model for real owner reports and common causes specific to your vehicle.

  2. 2
    Check for recalls

    Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.

  3. 3
    Get a professional diagnosis

    A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

Related Codes

U0115 Lost Communication With ECM/PCM B U0116 Lost Communication With Coolant Temperature Control Module U0117 Lost Communication With PTO Control Module U0118 Lost Communication With Fuel Additive Control Module U0119 Lost Communication With Fuel Cell Control Module U0121 Lost Communication With Anti-Lock Brake System (ABS) Control Module A U0122 Lost Communication With Vehicle Dynamics Control Module U0123 Lost Communication With Yaw Rate Sensor Module