2016 Toyota 4RUNNER Problems

What owners report

Owners of the 2016 4Runner most often report small but persistent electrical problems, chiefly rodent damage to soy-based wiring insulation in the engine bay and door lock actuators that stop locking or unlocking. A second cluster covers suspension hardware — broken front coil springs on TRD Pro models and leaking X-REAS struts and shocks — plus reports of clear coat peeling on the hood, roof and tailgate. Many of these appear well before 30,000 miles, and several complaints note that the dealer could not reproduce the symptom.

1. 1
   Electrical system

   Rodent damage to engine wiring harness

   • 11 complaints (14%)
   • median 12,000 mi at 1.5 yrs old (9 state mileage, few)
   • filed 2016–2023

   Owners describe chewed wiring insulation in the engine compartment, found after the vehicle shuddered, ran on fewer cylinders, threw warning lights, or lost a function such as four-wheel drive. Several complaints attribute the chewing to a soy-based coating on the wiring that attracts rodents, and one case also involved a nest built from hood insulation. According to the complaints, dealers identified bite marks and droppings, and owners say rodent damage was not treated as a warranty item. Reported from a few hundred miles to about 34,000 miles, often after the vehicle had been parked outdoors or at a campsite.

   What to check: Look for gnawed loom, droppings or nesting material around the firewall and hood insulation, and ask whether any harness sections have already been replaced.

   2 excerpts from owner complaints in NHTSA records

   “Toyota uses engine wiring that has a soy based coating. This encourages rodents to chew on them. We were camped (parked) and when we tried to drive the car it shuddered and the check engine light was on along with several other indicators. The car was running on five cylinders. We managed to get it to a Toyota dealer who told us of bite marks and droppings. In researching this on line we found reports of this happening in toyotas and hondas. …”

   NHTSA complaint #10881885, filed 2016-06, 10,000 miles

   “The wiring inside of the engine was chewed through by rodents. I drive the vehicle every day and it was serviced two days before. After performing some research, I found out that Toyota and other companies use soy based products to make wiring. This apparently attracts rodents as it is basically food for them.the vehicle was parked in front of my home in a marked parking spot. I have parked other (older) vehicles in front of my home for approximately 10 years without this problem. …”

   NHTSA complaint #11149822, filed 2018-11, 34,000 miles
2. 2
   Electrical system

   Door lock actuator stops locking or unlocking

   • 7 complaints (9%)
   • median 55,500 mi at 4.8 yrs old (4 state mileage, few)
   • filed 2020–2021

   Owners describe door locks that stop responding to the remote or the switch, usually one door at a time and often the unlock function first. Some report replacing the driver-side actuator only to find the problem returns or moves to another door, and a few say they now use the key. Complaints note the repair is expensive relative to the part, and that dealers quoted per-door replacement without offering a broader diagnosis. Mostly reported between roughly 45,000 and 60,000 miles, and several owners describe it as a common forum complaint on this generation.

   What to check: Lock and unlock every door several times with the remote and the interior switch, and listen for a weak or slow actuator; ask whether any door actuators have already been replaced.

   2 excerpts from owner complaints in NHTSA records

   “The SUV does not lock when I use the remote or when I try to lock it manually. I replaced the actuator in the driver side door which was the door that stays unlocked however to no avail. I am out a lot of money however I now believe there may be a bigger problem with something called bcm. I do not want to spend more money getting the issue diagnosed and repaired. This feels unfair to me that the locking system is broke and I risk the vehicle being stolen at such a young age of the vehicle.”

   NHTSA complaint #11324596, filed 2020-05, 53,000 miles

   “The door lock actuator on the passenger side door is going out. This is clearly a common problem with this make and year model. Several reviews I have read state that this has been an issue specifically with the front driver and passenger doors. I'm not sure why there has not been a recall on this issue. This is obviously a manufacturer issue vs a owner/user issue. Toyota really needs to consider a recall because this is not a cheap fix.”

   NHTSA complaint #11421709, filed 2021-06
3. 3
   Air bags

   Airbag non-deployment or unexpected deployment in a crash

   • 10 complaints (12%)
   • median 49,500 mi at 4.1 yrs old (3 state mileage, few)
   • 6 mention a crash, fire or injury
   • filed 2017–2026

   Complaints describe two opposite outcomes: frontal impacts where owners say no airbags deployed despite major damage, and incidents where airbags deployed in situations owners did not expect, such as a highway strike on road debris. Some owners describe injuries from deployment of the knee airbag. A separate set of complaints concerns Takata passenger-side inflator recalls and parts not being available. Spread across a wide mileage range, from about 26,000 to 53,000 miles in the reports that list mileage.

   Recall 19V741000Recall 19V005000Recall 16V937000

   What to check: Ask whether the passenger-side airbag inflator recalls (19V741000, 19V005000, 16V937000) have been completed, and confirm the work with a dealer.

   2 excerpts from owner complaints in NHTSA records

   “I hit a car that pulled out in front of me on the highway. I was going north bound and they attempted to take a left from a side street to go south bound. I was going 45 miles per hour and the other car was at a dead stop in front of me. I hit them just behind the drivers seat. My vehicle is not driveable, but yet the airbags did not deploy.”

   NHTSA complaint #11156961, filed 2018-12, 25,000 miles

   “On March 6, I was on South bound on Rt 29 in Culpeper County VA at the posted speed limit of 55mph when I hit a debris item on the road. I do not know what it was but it impacted the front skid plate and seems to be no other damage from the impact. There was no contact with the bumper, wheels or otherwise. There was no sudden change in speed or loss of control at all. The most dangerous result of this was the deployment of all the airbags (except passenger front airbag, there were no passengers). …”

   NHTSA complaint #11726606, filed 2026-03
4. 4
   Suspension

   Broken front coil springs and leaking X-REAS shocks

   • 6 complaints (7%)
   • median 18,445 mi at 2.9 yrs old (3 state mileage, few)
   • filed 2016–2025

   Owners of TRD Pro models report front coil springs cracking, in one case breaking in several places during ordinary highway driving, with dealers waiting on back-ordered parts. Other complaints describe the X-REAS sport suspension leaking from the front struts and rear shocks on vehicles used mainly on city streets. Complaints also mention leaking inner CV boots found at routine service and not covered under warranty. Spring failures reported around 41,000 to 114,000 miles; X-REAS leaks and CV boot seepage reported from about 18,000 to 58,000 miles.

   What to check: On TRD Pro models, inspect both front springs for cracks near the coil ends, and check the struts and rear shocks for fluid weeping; ask whether X-REAS components have been replaced.

   2 excerpts from owner complaints in NHTSA records

   “The 2016 4RUNNER trd pro is a limited production model. Toyota source the suspension components from an outside vendor. My right front spring failed, breaking I four places. The car has 41,000 miles and has only been used in normal highway driving -- no off-road. The front spring design is deficient. There is no taper at either end of the coil spring, leaving a knife edge touch the adjacent coil -- right where the spring broke. There are numerous examples of the same problem on the internet. …”

   NHTSA complaint #11365182, filed 2020-10, 41,000 miles

   “X-REAS sport enhancement system is failing in a vehicle (2016 Toyota 4 Runner) with 58,000 miles that has always been driven on city streets. Front struts and rear shock absorbers are both leaking and require replacement.”

   NHTSA complaint #11557202, filed 2023-11

Buying note. Check that the passenger-side airbag inflator recalls were completed, test every door lock, and look closely at the paint on the roof and hood. On TRD Pro or X-REAS-equipped trucks, have the front springs and struts inspected before purchase.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.