AutoCodes – Generic – U2021

U2021 Code - Invalid /Fault Data Received

Quick Answer

The Diagnostic Trouble Code (DTC) will set when an invalid or fault data received from a Control Module. Common causes include Faulty Control Module, Control Module harness is open or shorted, Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U2021 indicates Invalid /Fault Data Received.
Common causes: Common causes include Faulty Control Module, Control Module harness is open or shorted, Control Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 8,356

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 12, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
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Code U2021 Description

The Diagnostic Trouble Code (DTC) will set when an invalid or fault data received from a Control Module.

OBDII Code U2021 - Invalid /Fault Data Received - AutoCodes.com — U2021 Code - Invalid /Fault Data Received

What does this mean?

What are the Possible Causes of the DTC U2021?

Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC U2021?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U2021 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.