Code Definition

U0252 (87) — Lost Communication With Lighting Control Module – Rear B

System: Network Communication  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About U0252

U0252 is a generic (obd-ii standard) network communication diagnostic trouble code. It belongs to the U-prefix family of codes, which covers inter-module network communication (CAN, LIN, FlexRay, or similar) faults.

Scanning & clearing: Network (U) codes report communication faults between modules. When diagnosing U-codes, checking the vehicle's CAN bus integrity, supply/ground at each module, and reading all modules for related faults is usually the first step.

Because U0252 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The vehicle control modules communicate over the Controller Area Network (CAN) to exchange body and lighting control data. DTC U0252 sets when one or more modules fail to receive the required CAN messages from Rear Lighting Control Module B within a calibrated time period. A failure type byte of 87 indicates a missing or invalid message, meaning the module is not transmitting expected data on the network. This is typically caused by loss of power or ground to the lighting control module, a CAN circuit fault, or an internal module failure. The rear lighting control module drives rear lamp funct...

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