2018 Tesla Model 3 air bags problems

“The passenger seat back Occupant Classification System (OCS) sensor (Part #1920673-01-A) failed 3 times in under 22 months (Dec 2024, Dec 2025, Sep 2026), disabling the front passenger safety restraint system and airbag deployment logic”

“- When I start my car, I see the following error message appear: Front Left Safety Restraint System Fault. Also, the air bag disabled alert is displayed. Since the air bag is disabled, it puts me at grave risk if I were to get into an accident. - Many other Tesla owners have reported the same exact issue (RCM_a021 Front Left Safety Restraint System Fault). - Today, I took the car into the Tesla Service Center, they had to replace the entire harness. - No other symptoms were apparent...just all of a sudden the alert appeared.”

“Vehicle Information: Year/Make/Model: 2018 Tesla Model 3 Mileage at Incident: 45,000 miles Description of Safety Defect: A sudden and persistent "Safety Restraint System Fault" / "Front Passenger Safety Restraint System Fault" warning illuminated on the vehicle's primary touchscreen interface, indicating a complete compromise of the supplemental restraint and airbag system. Upon inspection by Tesla Service, the root cause was identified as physically broken/severed internal copper wiring within the first-row passenger seat harness assemblies. This breakage occurred purely due to the mechanical wear-and-tear of normal fore-and-aft seat tracking (including the standard vehicle "Easy Entry" setting). Because the electrical line cleanly severed, communication to the Occupant Classification System (OCS) sensor was totally cut off, preventing the vehicle from accurately detecting passenger occupancy or correctly configuring front passenger airbag deployment logic in a collision. Tesla has addressed this known design vulnerability internally via Service Bulletin SB-23-20-002, replacing the weak early-production parts with ruggedized components. However, because the…”

“Driving tghe 2018 Model 3 with around 75K miles, the warning "FRONT LEFT SAFETY RESTRAINT SYSTEM ISSUE" keeps popping up and staying on the center console. Tesla said car is out of warranty and have to pay upto $2000 to fix it.”

“My 2018 Tesla Model 3 displayed alert RCM_a056, “Front Passenger Safety Restraint System Fault.” The warning may affect correct detection of a passenger and operation of the passenger restraint/airbag system. Tesla quoted approximately $705 but has not identified the failed component or explained whether the condition is related to known front-seat wiring or occupant-classification failures. Tesla Repair Bulletin SB-21-17-005 recognizes that electrical harnesses in 2017–2019 Model 3 front seats can be damaged through repeated seat movement and trigger restraint-system alerts, although that bulletin specifically lists codes RCM_a021 and RCM_a022. I am reporting RCM_a056 because it affects the same general front-passenger safety-restraint system and appears to be reported by other early Model 3 owners. I am concerned that an occupant may not be properly classified or protected in a collision.”

“My Tesla Model 3 has a persistent RCM_a056 alert indicating a problem with the front passenger occupancy detection system. The unresolved fault affects the operation of the front passenger airbag system. I paid Tesla approximately $1,000 for a repair intended to resolve this problem. Tesla replaced multiple components associated with the passenger seat/occupancy detection system, including the sensor, wiring, and other safety-system components. The repair did not resolve the problem. The RCM_a056 alert remained unchanged after the repair. I returned the vehicle to Tesla for further diagnosis. Tesla tested the individual components and documented that they found “no issues present,” but the RCM_a056 alert remained. Tesla then recommended replacing the entire passenger seat assembly at a cost of approximately $3,000. When I asked what diagnostic evidence indicated that the seat assembly was defective, I was told that they had no specific evidence that replacing the seat would resolve the problem. They were unable to identify a failed component and indicated that replacing the entire seat was the only remaining repair they could suggest. I am concerned that this…”