2018 Tesla Model 3 seats 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”

“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…”

“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…”

“Component/system: The front passenger Occupant Classification System (OCS) in my 2018 Tesla Model 3. The vehicle is available for inspection on request. Description of the failure: The vehicle intermittently displays "Front passenger safety restraint system fault — service required]" on the center touchscreen. The alert first appeared on or about 4 years ago and has recurred approximately ~50 times since. The failure is strongly correlated with cabin temperature. It appears after the vehicle has been parked in direct sun in warm weather, and clears on its own once the cabin cools. It has not occurred in cooler ambient conditions. Safety risk: On this vehicle the front passenger seat uses a capacitive Occupant Classification System rather than a simple occupant-detection pad. The restraint control module uses OCS output to determine both whether the passenger airbag deploys and at what force. When the system faults, I have no way to know whether the passenger airbag is suppressed, will deploy at an inappropriate force for the occupant, or will deploy at all. This directly compromises frontal crash protection for anyone in that seat. I have been avoiding seating…”

“The front passenger safety restraint system is triggering an on-screen warning error that says service is required. This puts my front passenger at risk of death in the event of an accident. I have sent the manufacturer (Tesla) a request for service and received a confirmation of the errors with a list of parts to be replaced for a sum of $1200.65. I understand there is a service bulletin for this issue (Bulletin SB-19-20-003), but Tesla still will not fix it for free even though it is a safety issue. In the estimate, Tesla listed the following components as failure points that need to be replaced: 1) FIRST ROW OCCUPANCY SENSOR(1099592-00-F) 2) FIRST ROW - SEAT BELT REMINDER SENSOR BOX CLIP(1130363-00-B) 3) FIRST ROW SEAT HARNESS ASSEMBLY - RIGHT HAND(1489060-03-G) 4) AIRBAG HARNESS RETAINING CLIP(1028053-00-A) 5) BOLT,EHS,M6X19,[88],ZN,SMAT,ADH. - KNEE AND PASSENGER AIRBAG BOLT(1116594-00-B) 6) BOLT RC M6-1.25x26(1036655-00-A) 7) PASSENGER AIRBAG(1077823-00-G) 8) BOLT,HF,M6X7,STL[88],ZN,SHLDR[8X18]. (1105061-00-E)”

“The contact owns a 2018 Tesla Model 3. The contact stated that while opening the doors of the vehicle, the driver's side seat back unintendedly reclined and pressed down on the rear seat, causing the cushion to become deformed. The contact manually used the seat controls to return the seat to an upright position. There was no warning light illuminated. The contact stated that the failure was intermittent and only occurred while the doors were opened. A Tesla service center was contacted; however, an appointment was not scheduled for diagnostic test. The contact was provided an estimate for the repair. The vehicle was not diagnosed or repaired. The failure mileage was approximately 95,000.”