U0073 – Control module – data bus Off

Code | Fault Location | Probable Cause |
---|---|---|
U0073 | Control module - data bus Off (Buy Part On Amazon) |
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Table of Contents
- What Does Code U0073 Mean?
- What are the common causes of code U0073?
- What are the symptoms of code U0073?
- How do you troubleshoot code U0073?
- Codes Related to U0073
- Get Help with U0073
What Does Code U0073 Mean?
Vehicles are controlled by electronic means in some fashion or another. Whether actively controlled with a button or switch or passively controlled by a module, electrical systems are operated based on the input supplied to them and their output response. In turn, modules communicate those parameters with each other so all systems operate seamlessly. Communication is done via a data bus network, often referred to as a Controller Area Network (CANbus). The communication is crucial to ensure body, engine, transmission, anti-lock brakes, and all other systems are able to safely work together. When communication breaks down intermittently or fully between modules, a code is set in a module to indicate the failure. The code, U0073, can register in one or more modules: powertrain control module (PCM), transmission control module (TCM), anti-lock brake (ABS) module, or body control module (BCM) in various locations. Typically, the code sets in the module that experienced a loss of communication.What are the common causes of code U0073?
- The terminal pins have backed out at the module connector.
- A module's electrical connector is not fully seated.
- The CANbus are open or shorted to ground.
- Corrosion in various control module connectors.
- Intermittent or poor connections in the circuit connectors.
- The data link resistor is open or shorted.
- Water in various control module connectors.
- Shorted control module.
What are the symptoms of code U0073?
- The Check Engine light may be on.
- Instrument panel cluster warning lamps may illuminate.
- The transmission may not shift or defaults to 2nd gear.
- The door locks may cycle by themselves.
- The engine may not crank intermittently.
- A driver information center (DIC) message is displayed.
- The cluster gauges may operate erratically.
- Applying the brakes may cause the cluster to function erratically unwarranted chimes to sound.
How do you troubleshoot code U0073?
Because DTC U0073 is used in multiple modules, it can be difficult and time-consuming to find its root cause. The code indicates an error in communication, but symptoms that occur may seem unrelated. For example, a communication error at the instrument panel can cause the transmission to get stuck in limp-in mode. To diagnose DTC U0073, a good-quality digital volt-ohmeter (DVOM) is needed. You'll also require detailed wiring diagrams for your specific vehicle for all modules on the CANbus system, which you can request at many auto parts stores.
Codes Related to U0073
- U0100: Lost Communication With ECM/PCM
- U0101: Lost Communication With TCM
- U0102: Lost Communication With Transfer Case Control Module
- U0109: Lost Communication With Fuel Pump Control Module
- U0121: Lost Communication With ABS Control Module
- U0140: Lost Communication With Body Control Module (BCM)
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