What Is the U0401 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
The U0401 Code is a diagnostic trouble code that means Invalid Data Received from the Engine Control Module (ECM) or the Powertrain Control Module (PCM). It indicates that there’s a communication failure between two or more modules.
More About Error Code U0401
A control module is a computer inside your car that controls specific functions in a vehicle. There are many control modules in a vehicle that keep your car running. A control module will communicate with other control modules, passing information to ensure that your car is functional.
The Engine Control Module (ECM) is the computer that manages engine operation. It communicates with another module through a complex web of wiring known as the Controller Area Network (CAN) bus system. This information tells other modules how to function.
The PCM, or Powertrain Control Module, handles the information passed between control modules. It checks the information being passed. It’ll determine if this information is within the expected parameters. If the PCM detects invalid data received, then this code will be set.
Who Has the Lowest Price?
Some service centers will give you an online estimate to compare. Why drive around Town!?
What Are the Symptoms of a U0401 Code?
If you have U0401 Code, you’ll experience performance issues related to the ECM, or Engine Control Module. These symptoms include your vehicle refusing to start, an illuminated check engine light, and random loss of power. Depending on your manufacturer, your vehicle might deactivate safety systems, like traction control and stability control. In catastrophic failures, your vehicle may enter fail-safe or Limp Mode (where your vehicle shuts down less important parts of the car, like radio and air conditioning).
What Are Some Causes of a U0401 Code?
Typical causes of the U0401 code include disconnected or damaged wiring and or connectors to the ECM or PCM harness. Damage to the connectors or wiring harness can include being burnt, shorted, or corroded. This can also be caused by a dead battery or problems with the charging systems. Abnormal system voltages are also a common cause. Defective sensors, especially with the engine and drivability sensors, can also cause this code. However, these will also have their specific codes. Rarely, this code can be caused by a faulty control module.
How Serious Is the U0401 Code?
A U0401 Code is not always serious, but it is urgent. It needs to be fixed as soon as possible, as it can cause a loss of power or affect the engine’s performance. Its severity will depend on the cause of the code, so it’s important to determine the cause right away.
Can I Still Drive with a U0401 Code?
A U0401 code can affect your car’s drivability, especially if the code affects the traction control and stability control systems. If you have this code, it’s recommended to diagnose it as soon as possible.
How Easy Is It to Diagnose a U0401 Code?
It’s possible to check the cause of this code by yourself. However, it’s best to seek professional help when it comes to this code. Most of the time, this code requires diagnostic tools and equipment specific to your car’s make and model. For example, a generic scan tool may not provide you with the information that you need. Diagnostic procedures for this code may also require professional diagnostic skills.
How Difficult Is It to Inspect a U0401 Code?
The inspection process for a U0401 code begins with recording fault codes and freeze frames in the order that they were stored. Then, a visual inspection will be done to rule out circuit-poor electrical connections. Then, test the wiring for ground integrity, continuity, and resistance. Check the communication circuit between modules, test the CAN bus system, and rest the code. Then go out for a test drive. If the code persists, you’re dealing with a defective control module and control switch.
At this point, it’s highly recommended to seek professional help, if you haven’t already. You can try to refer to technical service bulletins. However, you’ll likely need special equipment and skills to truly fix the problem.
Need Additional Help with Your U0401 Code?
The U0401 code is a code that refers to invalid data received between the Powertrain Control Module, the Engine Control Module, and other control modules in your vehicle. It can be a difficult problem to fix by yourself as it often requires skills, information, and equipment specific to your make and model. If you have this code, it’s best to seek professional help.
You can do so by finding a repair shop in your area. Local professionals are important when dealing with this code, as U0401 Code can affect drivability.
Lastly, it can be helpful to check out the OBD-II database to refer to codes related to U0401 Code. This code can be caused by other codes, most commonly defective sensors. Likewise, this code may also come with subcodes that can make diagnosis easier.
U0401 Q&A
Common Error Codes
Browse All OBD-II Codes
Get Recall Alerts
All recalls are considered serious. Stay safe. Take care of any recalls ASAP. The good news? Recall repairs are free when performed at a local dealer.