In order to run smoothly, cars have a network of computers that send messages back and forth. These messages, sent by way of the CAN bus, include crucial data that controls the car’s suspension, braking systems, engine, and more. If your car’s Check Engine Light turns on, and you start to notice performance problems, there might be a problem with your car’s CAN bus.

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What does the engine code U0001 mean?

If your OBD-II scanner shows a U0001 code, it means that there’s a problem with your high-speed CAN wire (also called CAN high).

The CAN bus uses two wires for communication: CAN high (which sends messages faster) and CAN low (which is slower). “Bus” is just a technical term for the internal system that communicates data—like a highway system for your car’s messages to itself.

Usually, your car receives an automated message that says that your CAN bus is transmitting information correctly. If your car doesn’t receive this message, you’ll see a U0001 code pop up on your scanner.

How much will it cost to fix?

Most mechanics charge between $75 and $150 to diagnose your car’s U0001 code. Because a U0001 code can show up for lots of different reasons, it’s important to have it diagnosed by a professional—that way, you’ll know the next steps to take.

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What causes the U0001 engine code?

Here are a few possible causes of a U0001 engine code:

A faulty control module

An open or shorted control module harness

Poor connection in the control module circuit

Most often, the cause of a U0001 code is a break in the control module’s electrical circuit. This can happen if the components in the circuit are worn, damaged, or faulty.

Common symptoms of the U0001 engine code

The first sign of a U0001 code is an illuminated Check Engine Light.

Although it can be tricky to rule out other issues based only on the symptoms of a U0001 code, there are some other signs to look for. If your OBD-II scanner shows secondary codes (different codes that point to a failed engine module), there’s probably an issue with your CAN bus.

Also, if you notice performance problems with your car—like braking or engine troubles—this could confirm that the CAN bus isn’t working properly.

How serious is the U0001 engine code?

A U0001 code could indicate a variety of problems—from broken air conditioning to engine failure—so it’s best to take care of it right away. Although your car may be safe to drive, for now, a U0001 code could be the first sign of a more serious issue in the future!

Key Takeaway Without a working CAN bus, your car can’t send messages between its many computers, so it’s important to get it fixed as soon as possible.

Can I fix the U0001 engine code myself?

Since the CAN bus is an intricate system of wires and connectors, it’s best to have a professional take a look at it.

How does a mechanic fix a U0001 code?

First, a mechanic will visually inspect the CAN bus, looking for loose connections and broken wires. After repairing them, they’ll see if the code pops up again.

Then, if a certain car system isn’t working, the mechanic will look at the control modules for that system and fix any that are failed or burnt out.

If, on the other hand, the visual inspection doesn’t reveal any problems, the mechanic will check the manuals for your car’s specific make and model. This can help them to diagnose your car quickly and effectively.

Key Takeaway A mechanic can help to solve your U0001 error code and get you safely back on the road.

MORE: How to know if a mechanic is taking too long with repairs

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