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U0073 Fault Code

You can find information about the U0073 fault code on this page.

We have given it a seriousness of 9/10 with 1 being the least serious and 10 being the worst.

U0073 Short Description

"Control Module Communication Bus "A" Off"

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Description Icon Long Description

Fault code U0073 is a network communication code that is logged when the control module has detected a communication malfunction between the controller area network and one of the various control modules on board.

These include the engine control module (ECM), transmission control module (TCM), anti-locking braking system (ABS), or body control module (BCM).

This can cause a host of issues throughout the vehicle because of the importance of these various control modules.

Because of how complex the electronic systems onboard vehicles are becoming, almost every manufacturer is susceptible to this issue. However, BMW, Ford, Mercedes-Benz, Subaru, and Toyota are some of the most commonly searched alongside this type of fault code.

Warnings Icon Other Signs of This Problem

Due to the importance of the various electronic systems being able to communicate with their respective control modules, there can be a number of symptoms for this type of fault code.

One of the most obvious will be the presence of the Check Engine light on the dashboard.

Other signs can be found throughout any system of the vehicle, depending on how severe the issue is.

In terms of the powertrain, these can be problems like lowered performance, increased fuel consumption, stalling, and the engine not starting.

If the TCM is affected, automatic shifting may become impossible.

There may also be other electronic issues present throughout the vehicle if the body control module is affected.

Be sure to look out for fault codes that can pinpoint where the communication is breaking down. These can be U0100 to U0115.

Broken Down Icon What Could Be The Problem?

Because this is a communication issue, it is almost certainly caused by an electrical or electronic fault in one of the control modules.
It is very possible that one of the various control modules is faulty. Additionally, if any of these control modules are running on outdated software, this can cause them to malfunction, causing this fault code.

Other circuit issues like damaged or frayed wires and loose or damaged connections can also cause this breakdown in communication.

Other data network problems can also cause this fault code.

Fixed Icon Fixes

Fixes for this problem will typically focus on fixing electrical issues or software problems.

If there are any additional fault codes detected that can pinpoint the control module that has failed, this should be addressed first.

These control modules should be checked for software updates as well, as this can be a simple cause of this problem.

Any electrical issues like damaged wires or loose connections need to be fixed. The circuits for the control modules should be checked first. However, this can be a very extensive process.

Danger Icon Seriousness

Fault code U0073 should be considered a serious problem. Due to how much new vehicles rely on the various control modules, it is very important there is communication between them at all times.

This problem can result in dangerous driving conditions and cause damage to the vehicle. It is strongly recommended to have this fault code be fixed immediately.

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