U2021: Invalid /fault data received (Non SCP)

Network/CommunicationNetwork Communication

What does U2021 mean?

U2021 is a diagnostic trouble code indicating "Invalid /fault data received (Non SCP)". This code relates to your vehicle's network communication and should be diagnosed to determine the root cause. The severity level helps indicate how urgently this should be addressed.

Symptoms you may notice

  • Check engine light (MIL) illuminated on dashboard
  • Possible issues with network communication operation
  • Vehicle may enter reduced power mode (limp mode)

Estimated repair cost

Typical range in Australia (parts + labour)

$100 – $800 AUD

Common causes

  • Faulty network communication component
  • Wiring or connector issue in the related circuit
  • Failed sensor providing incorrect readings
  • Software/calibration issue requiring ECU update
  • Related component causing secondary fault

What should you do?

This code does not name the system it came from, so we will not tell you how urgent it is or whether the car is fine to keep driving. Do not read that as minor. Have the code read against your specific make and model, where the manufacturer-specific meaning can be looked up properly.

Get a diagnosis for YOUR car

Code U2021 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.

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Related codes

U2020Audio Center Amp is not responding
U2018Passenger Side Crash Sensor Communication Fault (Non SCP)
U2017Driver Side Crash Sensor Communication Fault (Non SCP)
U2015Signal Link Fault (Non SCP)