OBD Guide

U2021

Invalid /Fault Data Received

U2021 is an OBD-II diagnostic trouble code meaning: Invalid /Fault Data Received. Common causes: damage to the can bus wiring harness, poor contact in module connectors. Estimated repair cost: $6–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$6–56 (est.)

Symptoms

  • Check Engine light comes on
  • Malfunctions of the car's electronic systems
  • Incorrect operation of certain functions
  • Intermittent communication between modules

Causes

  • Damage to the CAN bus wiring harness
  • Poor contact in module connectors
  • Malfunction of one of the electronic modules
  • Problems with module power supply
  • Software failures in modules

How to Fix

  1. Check the integrity of the CAN bus wiring harness
  2. Inspect and clean contacts in module connectors
  3. Check power supply of all connected modules
  4. Read error codes from other modules
  5. Update module software

Related codes

FAQ

What does the U2021 code mean?

U2021 is an OBD-II diagnostic trouble code that indicates: Invalid /Fault Data Received

What causes a U2021 error code?

The most common causes of U2021 include: Damage to the CAN bus wiring harness; Poor contact in module connectors; Malfunction of one of the electronic modules; Problems with module power supply.

How do I fix a U2021 diagnostic trouble code?

To fix U2021: Check the integrity of the CAN bus wiring harness. Inspect and clean contacts in module connectors. Check power supply of all connected modules. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U2021?

Yes, but get it checked soon

How much does it cost to fix U2021?

The estimated repair cost for U2021 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat