Error code U0073 means ‘Control Module Communication Data Line “A” Closed’. This error code is generally triggered when the communication between the control modules of your vehicle is completely or partially lost. This code is only applicable to fuel-injected engine models manufactured after 2004. U0073 is a code that indicates a communication problem on the CAN bus. This code can be recorded because of communication interruptions among various modules. These include the engine control module, transmission control module, anti-lock brake system (ABS), and body control module.
The data network in your vehicle connects different modules and functions, much like the nervous systems of the human body. Over 40 modules are found in many vehicles that can communicate with one another.
The vehicle is equipped with high-speed, low-speed, two-wire, and single-wire networks as well as modules that translate. The modules receive information from different networks and pass it on to the modules that need it.
U0073 is not a fault code that applies to all new cars. This fault code is primarily for vehicles with a faster CAN bus network, which runs at different speeds.
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What are the possible causes of fault code U0073?
The U0073 code can be caused by:
- A CAN bus ‘A” with an open circuit
- Short circuit on the “A” CAN bus
- Circuit problems, such as damaged wiring and poor connections
What are the symptoms of fault code U0073?
Common symptoms of the code are:
- Engine power loss
- High fuel consumption
- The vehicle will not start
- All fault indicators on the instrument panel illuminate simultaneously
- The gearbox can fail to change or stay in second gear automatically
- The door lock may open or close on its own
- Warning messages can appear on the display of the driver
How to Fix Error Code U0073?
You can start by checking the technical service bulletins that are available for your car. If you are able to access the fault codes, it may be that the problem is caused by a known fault. Check if you can access the fault codes. You will need to verify the modules if these fault codes are related to them.
Locate all the data bus connections in your car. Visually inspect connectors and cables. Look for signs of fraying or burn marks on the cable. Examine the terminals by removing the connectors. Check for burn marks or rust. Clean the terminals with an electronic spray and brush if they need to be cleaned. Let them dry, and then apply dielectric silicone to the terminal contact points. Connect the module to the scanner tool. Clear all fault codes if it connects and then check if the code returns. If the code does not return then it is resolved.
If the communication still isn’t possible or the code is returned, it is best to unplug each control module and then check if communication has been established. Disconnect the negative terminal of the battery before disconnecting any connector for a control module. Disconnect the module connector, and then reconnect the battery cable. If you still cannot communicate, contact a technician.
