OBD-II code U0145 means that one of the vehicle's control modules (most often the powertrain control module) has stopped receiving messages from Body Control Module E (BCM-E) over the CAN communication network. This is a network communication fault, not a fault of a specific sensor or actuator, so BCM-E is either not transmitting, not powered, or not properly connected to the data bus. Modern vehicles use multiple body control modules (A, B, C, D, E, etc.) that each handle a different group of body functions.
Damaged wires, corroded pins, loose connectors, or water intrusion at the BCM-E harness are the most common cause of lost-communication codes. Inspect the connector and harness before replacing any module.
A blown fuse, failed relay, broken ignition feed, or poor ground can prevent BCM-E from powering up and joining the network. Voltage and ground should be verified at the module before condemning it.
Excess resistance, a short between CAN-H and CAN-L, an open circuit, or failed termination on the bus segment BCM-E shares can prevent its messages from being seen by other modules.
A failing module on the same CAN segment can drag the bus voltage down and silence BCM-E, even when BCM-E itself is healthy. Identifying the offending module often requires disconnecting modules one at a time while watching bus activity.
The BCM-E itself can fail internally, though this is less common than wiring or power issues. Replacement on most vehicles requires programming or coding with a factory-compatible tool.
The module reporting the lost communication is rarely the cause. It should only be suspected after the BCM-E, its wiring, power, ground, and the bus itself have all been ruled out.
Almost never. U0145 means another module has lost communication with BCM-E, and the overwhelming majority of cases are caused by wiring, connectors, or power/ground issues at BCM-E, not the module that set the code. Replacing the PCM because of a U0145 is one of the most common and most expensive misdiagnoses and should only be considered after BCM-E, its harness, and the bus have all been verified good.
In most cases the engine will still start and run, but features handled by BCM-E such as lighting, locks, or other accessories may be disabled or behave erratically. It is generally safe to drive to a repair facility, but the issue should be addressed promptly because network faults can trigger unpredictable electrical behavior or set additional codes.
On most modern vehicles, a new body control module requires programming, coding, or configuration with a factory-compatible scan tool so it can communicate with the rest of the network and match the vehicle's options. A used module typically requires the same procedure, and in some cases a security or immobilizer learn is also needed.
Manufacturers split body-control functions across several modules (often labeled A, B, C, D, E, and so on) that each handle a different group of features, such as lighting, climate, security, or accessory control. The exact assignment of BCM-E varies by manufacturer and model, so the symptoms of U0145 depend on which functions BCM-E manages in the specific vehicle being diagnosed.