Owners describe airbags that fail to deploy entirely during significant frontal and side-impact collisions (speeds ranging 5–55 mph), leaving occupants to strike the steering wheel, dashboard, and interior components without cushioning. Several owners report partial or delayed deployment—bags inflating after impact has already occurred or failing to fully expand on one side while the other deploys normally. Injuries include fractured sternums, broken facial bones, cracked ribs, head concussions, chest and back trauma, and spinal injuries.
A critical subset of complaints links airbag failure to rodent damage. Mice and rats chew through door harnesses connected to airbag sensors—a problem owners attribute to bio-based (sugar cane) wiring insulation that attracts rodents. One owner discovered an unscreened 12-inch fresh-air intake hidden under the windshield wiper cowls and unscreened trunk vents allowing rodent entry. That incident disabled the airbag, pre-collision system, ABS, stability control, and seatbelt pre-tensioning across multiple warning lights. Repair cost $1,387; the owner fixed a second incident with a $60 used harness and sealed the vents himself with hardware cloth. Toyota denies liability despite the bio-based material selection.
One owner's horn stopped working due to a faulty spiral cable also controlling the airbag circuit—a part previously recalled in older Prius models. Toyota declined to recall or assist, quoting over $800 for repair.
A separate recall for Takata airbags exists with no remedy available from Toyota.
Failure modes owners describe
Airbag non-deployment in collision
Airbags fail to deploy during front-end, side-impact, or multi-vehicle collisions at various speeds (5–55 mph), leaving occupants unprotected and causing injuries from impact with steering wheel, dashboard, or other vehicle structures.
When: During collision events; mileage ranges from 1,200 to 150,000 miles
Symptoms owners cite: No airbag deployment despite significant frontal or side impacts; Occupants hitting steering wheel, dashboard, or interior components without cushioning; Airbag warning light illuminates but bags do not inflate; Seat belts also fail to restrain occupants properly in some cases
Repairs/costs cited: Sensor replacement reported in at least one case; vehicle typically totaled following collision
Recalls/TSBs owners mention: Toyota stated in multiple cases 'no evidence of a manufacturing or design defect with the airbag or seat belts' despite collision investigations
Partial or delayed airbag deployment
Airbags deploy but fail to fully inflate or deploy after impact has already occurred, reducing protective benefit and allowing occupants to strike hard surfaces.
When: During collision events; noted at 23,000 and 150,000 miles
Symptoms owners cite: Steering wheel airbag deploys after driver's head has already struck wheel; Knee airbag deploys after occupant's knees impact lower dash; Driver-side airbag fails to fully inflate while passenger-side deploys normally; Airbag deployment occurs too late to prevent injury
Repairs/costs cited: No repair information provided; vehicles typically destroyed
Rodent damage to airbag harness and wiring
Mice and rats chew through door harnesses and wiring connected to airbag sensors, disabling the airbag system along with pre-collision, ABS, stability control, and seatbelt pre-tensioning. Damage traced to bio-based materials in wiring insulation that attract rodents; unscreened fresh-air intake and trunk vents allow entry.
When: Reported within first few years of ownership; one case at low mileage (within 3 years)
Symptoms owners cite: Multiple warning lights: airbag, pre-collision system, hybrid system, slip indicator, brake system; Cruise control malfunction (displays 'E3' error); Chewed wires in door harness visible to mechanic and owner; Subsequent rodent damage to passenger-side harness a few months later; Metal 'sliding' sound in front passenger door panel (possible loose debris)
Repairs/costs cited: First incident: $1,387.06 dealership repair (harness replacement, insurance covered $887.06 after $500 deductible); owner obtained $60 used replacement harness from eBay for second incident. Owner prevented further access by covering unscreened HVAC fresh-air intake (12×9 inch opening under windshield wiper cowls) and trunk vents with 1/4-inch hardware cloth.
Recalls/TSBs owners mention: Toyota denied liability and responsibility for rodent damage caused by bio-based materials; no recall issued
Airbag system wiring defect (spiral cable)
Faulty spiral cable in steering column loses continuity, disabling horn and affecting airbag deployment circuit. Part was previously recalled in older model years but not in 2012 Prius.
When: Mileage not specified
Symptoms owners cite: Horn inoperative; Spiral cable failure diagnosed by dealer
Repairs/costs cited: Dealer quoted over $800 for replacement
Recalls/TSBs owners mention: Toyota case #210-128-2281 opened; manufacturer declined to treat as safety concern or offer recall assistance
Airbag sensor failure to trigger deployment
Airbag sensor fails to activate the deployment system during multi-vehicle collision with sufficient force, even though sensor replacement was later found necessary during repair.
When: Reported at high-impact, multi-vehicle incident
Symptoms owners cite: Airbag does not deploy despite severe impact damage (over $11,000 in repairs); Airbag sensor subsequently replaced during repair process
Repairs/costs cited: Airbag sensor replaced; total vehicle damage exceeded $11,000
Takata airbag recall—no remedy available
Vehicle subject to NHTSA Takata recall but Toyota has not provided a remedy. Owner expresses concern about instability of ammonium-nitrate-based propellant used by Takata.
When: Recall status; no failure yet reported by this owner
Symptoms owners cite: Airbag recall notice received; no remedy implemented
Recalls/TSBs owners mention: NHTSA shows recall but no remedy available from Toyota
Synthesized from 39 NHTSA owner complaints — unverified consumer
allegations, summarized for patterns. The verbatim filings appear below.