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  • The U0001 code stands for “High-Speed CAN Communication Bus.” It means the PCM detects an error within the high-speed CAN communication bus circuit or modules.
  • CAN bus circuit issues, defective battery or corroded terminals, or a malfunctioning control module may trigger the code.
  • Stalling and difficulty starting are some of the most common symptoms associated with the U0001 code.

Modern vehicles are equipped with various types of sensors and computers. To keep your ride running smoothly, there must be uninterrupted communication between these components. That’s the reason why control area network (CAN) systems were developed.

The high-speed CAN bus is a data network that links your ride’s control modules that communicate at a relatively fast rate. When your vehicle’s powertrain control module (PCM) detects that there’s something wrong with a CAN bus circuit or control module, it will trigger the U0001 code.

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What Does the U0001 Code Mean?

Diagnostic trouble code (DTC) U0001 stands for “High Speed CAN communication bus.” Your vehicle’s CAN system connects various modules in your vehicle. Each module has a unique identification code for communicating on the network.

The high-speed CAN operates at a certain data rate. U0001 is a communication system diagnostic code that can be logged when the PCM detects an error within the high-speed CAN communication bus circuit or modules.

Note: The definition of code U0001 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

mechanic using a multimeter to perform car tests
Diagnostic and repair procedures for the U0001 Code can differ per vehicle manufacturer.

What Are the Common Causes of the U0001 Code?

  • CAN bus circuit issue
  • Defective battery or corroded terminals
  • Malfunctioning control module

What are the Common Symptoms of the U0001 Code?

How to Diagnose the U0001 Code

The tricky thing about network codes is a totally unrelated system can cause the issue, so be very careful when you’re trying to diagnose or fix U series codes.

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Also, keep in mind that while code U0001 is a generic powertrain code and can present similar symptoms and triggers across various makes and models, its diagnostic and repair procedures can differ per vehicle manufacturer.

If you’re not familiar with the process of diagnosing trouble codes on your own, it might be best to leave the job to a certified mechanic. However, if you think you have the right tools and knowledge to do the job yourself, then feel free to diagnose the problem on your own.

To help you out, here’s a video that shows you what the process might involve:

How to Fix the U0001 Code

Fixing a U0001 code isn’t an easy task. If you’re not an experienced automotive DIYer, it’s a good idea to bring your vehicle to a certified mechanic to ensure that proper tests and repair procedures are carried out.

But if you think you can get the job done yourself, make sure you have the right repair tools on hand.  We recommend reading your vehicle’s repair manual or checking out an online database for vehicle-specific repair information.

About The Authors
Written By Automotive and Tech Writers

The Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : OBD-II Trouble Codes Tagged With : ,
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Alex Regado

Very informative..

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