OBD Guide
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U121C

Hard Disk Drive Access

U121C is an OBD-II diagnostic trouble code meaning: Hard Disk Drive Access. Common causes: physical damage to the hard drive, hard drive power problems. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Multimedia system does not work
  • Slow system boot
  • Frequent display malfunctions
  • Loss of saved data
  • The system does not recognize the hard drive

Causes

  • Physical damage to the hard drive
  • Hard drive power problems
  • Contact corrosion
  • Hard drive overheating
  • Software system failure

How to Fix

  1. Check hard drive connection
  2. Check the power of the hard drive
  3. Clean contacts from corrosion
  4. Replace the hard drive if necessary
  5. Update system software

Related codes

U121DU121E

FAQ

What does the U121C code mean?

U121C is an OBD-II diagnostic trouble code that indicates: Hard Disk Drive Access

What causes a U121C error code?

The most common causes of U121C include: Physical damage to the hard drive; Hard drive power problems; Contact corrosion; Hard drive overheating.

How do I fix a U121C diagnostic trouble code?

To fix U121C: Check hard drive connection. Check the power of the hard drive. Clean contacts from corrosion. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U121C?

Yes, but get it checked soon

How much does it cost to fix U121C?

The estimated repair cost for U121C is $33–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat