U0140 code — how to fix error fast

If you’ve noticed that there may be something off when it comes to the electronic features of your car’s interior and the scanner tool reveals the code U0140, you may be dealing with one of the most common error codes. While it’s not likely to cause significant engine or transmission damage, most drivers are pretty ignorant of the U0140 code meaning and what it stands for in your car.

That’s why our team wanted to help you deal with the code and give you a few tips on the best ways of diagnosing and fixing the issue. So, let’s get straight to it by giving you an overview of the code’s meaning and the main potential reasons behind it.

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What does the U0140 code mean?

The U0140 code is a communication error code that appears when there is a problem with the communication between different control modules in a vehicle. In other words, it means that there is a problem with the network communication within the car. The code is often accompanied by a “lost communication with body control module” message.

To make things simpler – the code can affect the performance of your vehicle if the communication issue is with the most important modules, or it can compromise the usability of your car’s electrical features.

What causes the U0140 code?

There are several possible reasons behind the code U0140 and it takes going through all of them if you want to figure out the exact source of the problem. You can do it by checking these potential causes:

Faulty body control module (BCM)

The body control module (BCM) is responsible for controlling various electrical and electronic systems in a vehicle, such as the interior lights, power windows, and door locks. If the BCM is faulty, it can lead to communication errors and trigger the U0140 code.

Wiring problems

If there are wiring problems in the vehicle, such as damaged wires or loose connections, it can cause communication errors and trigger the U0140 code.

Dead battery

If the vehicle’s battery is dead or has low voltage, it can cause communication errors and trigger the U0140 code.

Software issues

If there are software issues with the vehicle’s control modules, it can cause communication errors and trigger the U0140 code.

Which car models does the U0140 code affect the most?

The U0140 code can affect various car models, but it is more common in certain vehicles. Some of the car models that are most affected by the U0140 code include:

• Ford F-150: The U0140 code has been reported to occur in various model years of the Ford F-150, particularly in trucks with higher mileage.
• Chevrolet Silverado: The U0140 code has been reported in various model years of the Chevrolet Silverado, often due to faulty BCM or wiring issues.
• Dodge RAM: The U0140 code has also been reported in various model years of the Dodge Ram, particularly in trucks that have experienced electrical problems in the past.

How to diagnose the U0140 code

To diagnose the U0140 code, you will need a diagnostic scanner that can read the code and the communication between control modules. That’s at least the first thing that a mechanic would do, but there are some other ways of diagnosing the code:

Connect the diagnostic scanner

Connect the diagnostic scanner to the vehicle’s OBD-II port and turn on the ignition. You will be able to read the code and it takes getting an affordable scanner tool to just read the code so you don’t have to go over the line by paying hundreds of dollars for one.

Look for other associated codes

You can read the code U0140 and also check for signs of other codes that may have been associated with the U0140 code. This way you can narrow down the source of the issue since this code is a pretty general one.

Check communication

Check the communication between the control modules using the diagnostic scanner. If there is a problem with the communication, it can help pinpoint the cause of the U0140 code.

Check the BCM

Check the body control module (BCM) for any signs of damage or corrosion. If the BCM is damaged, it will need to be replaced. It’s also one of the most common reasons behind the code and it’s always recommended to check it before coming to a conclusion on what might have caused the code.

How to fix the U0140 code

There are several ways to fix the U0140 code, depending on the underlying cause of the issue. Here are some of the most common methods you can use after the scanning phase:

Check and repair the wiring and connections

One common cause of the U0140 code is faulty wiring or poor connections between the ECM and BCM. Mechanics will often begin by visually inspecting the wiring and connections to see if there are any issues, such as frayed wires or loose connections. If any problems are found, they can be repaired or replaced as necessary.

Replace the body control module

In some cases, the BCM itself may be faulty and need to be replaced. This is more likely if the U0140 code is accompanied by other BCM-related codes. Replacement BCMs can be sourced from a dealership or aftermarket supplier and will need to be programmed to work with your specific vehicle.

Update the software or firmware

Sometimes, the U0140 code may be caused by outdated software or firmware in either the ECM or BCM. In these cases, mechanics can update the software to the latest version using specialized tools. This is typically done by connecting a diagnostic scanner to the car’s OBD-II port and following specific instructions.

How to prevent the U0140 code

Preventing the U0140 code can sometimes be as simple as doing some regular maintenance tasks and following up on the maintenance schedule. Of course, you’ll also need to carefully inspect the modules from time to time to make sure everything is working accordingly, but here are the main ways you can accomplish this:

• Checking the battery regularly and replacing it when necessary
• Checking the wiring for any signs of damage or corrosion
• Updating the control module software when needed
• Following the manufacturer’s recommended maintenance schedule

By following these preventative measures, drivers can avoid the U0140 code and other communication errors in their vehicles.

Our take

In the end, the code U0140 may not be as harsh as some other codes that directly refer to the communication of the ECM or the TCM, but it still needs to be repaired right away to prevent further electrical issues. So, we hope that this guide will suffice in giving you some initial pointers upon which you can base your investigation of the root cause and easily fix and prevent the code from happening again.