2019 Toyota 4Runner: Mouse infestation due to soy products
Common wear/failure (not a recall)
Symptoms
Owners of the 2019 4Runner report: mouse infestation due to soy products. CarComplaints.com lists 1 owner complaints, average mileage 15,000 miles.
NHTSA has 2 owner complaints for the 2019 4Runner in this area. Examples:
- NHTSA complaint ODI #11652743 (filed 04/04/2025): “My vehicle keeps leaking inside from the ac drip line and it's been cleared multiple times and it still keeps happening and it floods the whole bottom of the passenger side floorboard and becomes soaked through which can cause erosion, electrical issues, mold …”
- NHTSA complaint ODI #11288605 (filed 12/12/2019): “By design, which toyota motor sales usa inc. acknowledges, the 2019 4runner sr5 windshield and front window defrost functions with external air only, and will not function with recirculated vehicle cabin air. this exposes vehicle occupants to potentially haza…”
Likely causes
Sources do not establish a single root cause; diagnosis is needed. Owner-reported fixes are listed below.
Fix, in plain English
Most common owner-reported solutions on CarComplaints.com: new heater box (1 reports). Check for open recalls and extended warranty coverage with a dealer before paying out of pocket.
DIY difficulty: Pro
Opening the A/C system requires refrigerant recovery equipment, and US EPA Section 609 certification is required to service vehicle A/C for compensation. (Our assessment.)
Cost
CarComplaints.com owners report a typical repair cost of about $4,200 (owner-reported average, not a quote).
Typical parts (search links, no affiliate codes)
AutoZone · O'Reilly · Advance · RockAuto
Sources
- CarComplaints.com: Mouse infestation due to soy products (2019 4Runner)
- NHTSA complaints API, 2019 4Runner
Page last updated .