AutoCodes – Infiniti – U121B Infiniti

U121B Infiniti Code - Hard Disk Drive Communication Error

Quick Answer

Integrates Hard Disk Drive (HDD) allowing map data and music data to be stored. Common causes include Faulty Audio and Video (AV) Control Unit, Audio and Video Control Unit harness is open or shorted, Audio and Video Control Unit 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: U121B Infiniti indicates Hard Disk Drive Communication Error.
Common causes: Common causes include Faulty Audio and Video (AV) Control Unit, Audio and Video Control Unit harness is open or shorted, Audio and Video Control Unit 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 455

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 May 04, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U121B Infiniti Description

Integrates Hard Disk Drive (HDD) allowing map data and music data to be stored. It is the master unit of the MULTI AV system, and it is connected to each control unit by means of communication. It operates each system according to communication signals from the AV control unit. The AV control unit includes the audio, hands-free phone, voice control, navigation, and vehicle information functions. It is connected to ECM and combination meter via CAN communication to obtain necessary information for the vehicle information function.
The Diagnostic Trouble Code (DTC) sets when the Audio and Video (AV) Control Unit detects an internal malfunction of the Audio and Video (AV) Control Unit (HDD communication error).

OBDII Code U121B Infiniti - Hard Disk Drive Communication Error - AutoCodes.com — U121B Infiniti Code - Hard Disk Drive Communication Error

What does this mean?

What are the Possible Causes of the DTC U121B Infiniti?

Faulty Audio and Video (AV) Control Unit
Audio and Video Control Unit harness is open or shorted
Audio and Video Control Unit circuit poor electrical connection

How to Fix the DTC U121B Infiniti?

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 U121B Infiniti 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.

Frequently Asked Questions about U121B Infiniti Code

1. What are the common symptoms of OBDII code U121B (Infiniti) for Hard Disk Drive Communication Error?

The common symptoms include issues with the vehicle's infotainment system, navigation system, or audio system malfunctioning.

2. What are the possible causes of the U121B code (Infiniti) indicating a Hard Disk Drive Communication Error?

The code may be triggered by a faulty hard disk drive unit, loose connections, wiring issues, or a malfunctioning control module.

3. How can I diagnose the U121B code (Infiniti) related to Hard Disk Drive Communication Error?

Diagnosing this code involves checking the connections to the hard disk drive, inspecting the wiring for any damage, and testing the control module for proper functionality.

4. Can a DIY enthusiast repair the U121B code (Infiniti) associated with Hard Disk Drive Communication Error?

Repairing this code may require advanced diagnostic equipment and technical knowledge, so it is recommended to seek assistance from a professional mechanic or dealership.

5. Is it safe to continue driving with the U121B code (Infiniti) indicating Hard Disk Drive Communication Error?

It is not recommended to drive the vehicle with this code unresolved, as it may lead to further malfunctions in the vehicle's electronic systems.

6. How much does it typically cost to repair the U121B code (Infiniti) for Hard Disk Drive Communication Error?

The cost of repair can vary depending on the specific issue causing the code, but it may involve replacing the hard disk drive unit, repairing wiring, or reprogramming the control module.

7. Are there any preventive measures to avoid the U121B code (Infiniti) related to Hard Disk Drive Communication Error?

Regularly checking and maintaining the vehicle's electronic systems, including the hard disk drive unit, can help prevent issues that may trigger this error code.

8. Can a software update resolve the U121B code (Infiniti) for Hard Disk Drive Communication Error?

In some cases, a software update provided by the manufacturer may address communication errors with the hard disk drive unit, so it's worth checking with a dealership for potential updates.

9. What are the long-term consequences of ignoring the U121B code (Infiniti) for Hard Disk Drive Communication Error?

Ignoring this code may lead to complete failure of the infotainment system, navigation system, or audio system, resulting in a loss of functionality.

10. How can I clear the U121B code (Infiniti) associated with Hard Disk Drive Communication Error from the vehicle's system?

After the underlying issue has been diagnosed and repaired, the code can be cleared using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes to reset the system.