This code indicates that the main vehicle network has lost communication with the Rear Lighting Control Module B. It means the primary computer can no longer send or receive data from this specific module, disrupting normal rear lighting functions.
A blown fuse, open circuit, or poor ground connection is the most common reason a module stops communicating.
The module itself may have suffered an internal hardware failure, preventing it from powering up or transmitting data.
An open circuit, short to power, or short to ground in the communication wires between the rear module and the main network.
Moisture intrusion in the rear body area can cause terminal corrosion, breaking electrical contact for power or data.
Rarely, the module controlling the network may have failed, though this is highly unlikely compared to wiring or rear module issues.
Yes, the rear lighting functions managed by this module will likely fail, operate erratically, or remain stuck in a default state.
No, it is unsafe and often illegal to drive without properly functioning rear lights, turn signals, or brake lights.
No, it is very rare for the PCM to cause a U0252 code. Drivers are frequently told to replace the PCM, but the problem is almost always isolated to the rear lighting module, its power/ground, or its wiring.
They are often located in areas prone to moisture and vibration, leading to internal corrosion or damaged solder joints over time.