2005 Mazda 3 U0151 Fault: Lost Communication with RCM Module - CAN B Bus Issue

Hi, I'm experiencing a persistent issue with my 2005 Mazda 3 1.6L (1600cc) model. The airbag warning light is illuminated, and I've been diagnosed with OBD-II fault code U0151 — indicating lost communication between the vehicle's RCM (Rear Control Module). The RCM was repaired in the USA, but the problem persists. My Mazda 3 uses two CAN bus systems: CAN C (HSCAN) and CAN B (MSCAN). CAN C is functioning correctly. The ECU and instrument cluster are connected to this bus, with stable voltage readings: CAN C+ = 2.57V, CAN C- = 2.36V. However, the CAN B bus is not working properly — I cannot establish communication with the RCM module. Devices on this bus include the instrument cluster, audio system, airbag control module, and the passenger compartment microcomputer. The measured resistance on the CAN B line is 60 ohms, which appears normal. The voltage readings for CAN B are: CAN B+ = 2.56V, CAN B- = 2.34V. This raises a significant concern because OBD-Codes.com lists expected values as CAN B+ = 0.5V and CAN B- = 4.5V — but I'm unsure if these values are accurate for the 2005 Mazda 3. Could this discrepancy be due to model-specific variations? Is there a known fix or diagnostic procedure specific to this vehicle? Any insights from owners or technicians who have encountered U0151 on a 2005 Mazda 3 would be greatly appreciated. Thank you in advance for your help.