U0274 indicates that the Powertrain Control Module (PCM) has lost communication with Lighting Driver Control Module B, which manages various lighting functions. The loss of communication can cause lighting systems to malfunction or operate intermittently.
The module itself may have internal failures, such as damaged circuitry or burned-out components, preventing it from responding to the PCM.
Wire harnesses between the PCM and the lighting driver can become corroded, cracked, or pinched, breaking the communication link.
A connector at either the PCM or the lighting driver may have pins that are bent, corroded, or not fully seated, causing intermittent contact.
Insufficient voltage or a poor ground for the lighting driver module can cause it to shut down, resulting in loss of communication.
Only after ruling out the module, wiring, and connectors should the PCM’s communication circuitry be considered as a possible cause.
It is possible but uncommon. The PCM is usually the last component to be considered after confirming the driver module, wiring, and connectors are functioning correctly.
No. The issue is typically isolated to the driver module, its wiring, or a connector. Replacing the whole lighting assembly is rarely necessary.
Clearing the code will turn off the warning light temporarily, but if the underlying communication fault remains, the code will return.
Most lighting functions will still operate, but intermittent loss of critical lights (e.g., headlights or turn signals) can be a safety hazard. Repair is recommended before continued use.