The air conditioning dye injection tool kit has been developed to aid in identifying the location of air conditioning refrigerant leaks. The procedures outlined in this Service Bulletin aid in locating, inspecting, and repairing refrigerant leaks.
full bulletin at NHTSA ↗2016 Toyota 4Runner electrical problems
severe Owners of the 2016 Toyota 4Runner have filed 17 NHTSA complaints about the electrical, typically surfacing around 29,922 miles at roughly $850 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See electrical across all vehicles →
Failure mileage
Complaints
17
Recalls
0
Avg fix
$850
| Model year | electrical complaints |
|---|---|
| 2012 4Runner | 3 |
| 2013 4Runner | 4 |
| 2014 4Runner | 24 |
| 2015 4Runner | 12 |
| 2016 4Runner (this page) | 17 |
| 2017 4Runner | 5 |
| 2018 4Runner | 4 |
| 2019 4Runner | 8 |
1fire
When does it fail?
Of the 17 electrical complaints filed for the 2016 Toyota 4Runner, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Among the 16 model years of Toyota 4Runner in our records for electrical problems, this one ranks #2 by owner-complaint volume.
Electrical accounts for 22% of all owner complaints filed against this vehicle, across 8 categories tracked.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering electrical on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
DP: The Data Communication Module (DCM) in the subject vehicles are equipped with software to identify the location of the vehicle using the Global Positioning System (GPS) to support features of the Safety Connect system. Due to incorrect programming in the DCM software, after November 2nd, 2019, the GPS coordinates for this system will be calculated incorrectly. This will cause the system to use incorrect vehicle coordinates if one of the system?s features is activated.
full bulletin at NHTSA ↗TI: TECHNICAL INSTRUCTIONS FOR LIMITED SERVICE CAMPAIGN K0P CUSTOMER SUPPORT PROGRAM 19TE12 SAFETY CONNECT SYSTEM ? VEHICLE LOCATION INACCURATE CERTAIN 2013 ? 2019 MODEL YEAR 4RUNNER 2011 ? 2017 MODEL YEAR LAND CRUISER 2013 ? 2017 MODEL YEAR PRIUS 2012 ? 2017 MODEL YEAR PRIUS V 2016 ? 2017 MODEL YEAR MIRAI Updated 010/25/2023
full bulletin at NHTSA ↗TSB: The Immobilizer and Smart Key Reset is a feature that allows the registration of new keys when all master keys are lost. Once the system is reset, all previously registered keys will be erased. Follow the procedures in this bulletin to reset a vehicle Immobilizer or Smart Key system.
full bulletin at NHTSA ↗TSB: Some 2016 ? 2018 model year Toyota vehicles equipped with Entune? Audio (version 01013E), Entune? Audio Plus (version 010156 or 01015C), or Entune? Premium Audio (versions 010171, 010170, or 01017D) may exhibit one or more of the following conditions: ?Head unit reboots at a specific location. ?Abnormal Destination Search app operation. ?Rebooting caused by no songs on the USB-connected iPhone. ?A one-time reboot after ignition is cycled to ACC-ON. ?Audio stays muted after the key is cycled.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 17 complaints center on two major defects: rodent-chewed wiring and door lock actuator failures.
Rodent damage dominates: Multiple owners report rodents chewing through engine wiring and main harnesses at low mileage (12,000–30,000 miles), even within the first three weeks to one year of ownership. The damage triggers check-engine lights, transmission hesitation, reduced cylinder firing, shuddering, and acceleration problems. Owners cite research linking Toyota's soy-based wire coating to rodent attraction. Harness replacement runs $3,500–$5,700, with labor reaching $7,900 if engine removal is needed. Parts take 10–14 days to ship; Toyota excludes rodent damage from warranty. At least one owner experienced harness replacement twice, with the problem recurring.
Door lock actuators fail early: Multiple owners report driver and passenger side locks no longer responding to remote fob or manual interior switches, with complaints appearing on forums as a pattern. Repairs cost $550–$800 per door. One owner replaced the actuator and still couldn't lock the vehicle, suspecting a larger electrical issue (BCM). The safety implications are real—an unlocked door can invite intrusion; a locked door can trap an incapacitated passenger post-accident.
Lesser issues: One owner reported burning electrical smell and fire-hazard smoke from seat warmer wiring while driving. Another experienced repeated electrical dropout (radio, USB, blower, dash cluster) at highway speeds due to a loose, broken battery mount. Rear-view camera screen blackouts were also reported.
Same Toyota 4Runner electrical reports on nearby years: 2014 · 2015
Failure modes owners describe
Rodent damage to wiring harness (soy-based coating)
Rodents chew through engine wiring and main harness, causing electrical damage and drivability issues. Owners report Toyota uses soy-based wire coating that attracts rodents. Multiple owners cite needing complete harness replacement ($3,500–$5,716 in documented cases) after rodent damage occurs within first year or at low mileage.
When: 12,000–30,000 miles; some within first 3 weeks/year of ownership
Symptoms owners cite: Check engine light and multiple warning lights (ABS, brake, others); Transmission not shifting properly, struggling to reach 40 MPH, not entering eco mode; Vehicle running on reduced cylinders (five instead of eight), shuddering; Hesitation on acceleration; Vehicle shake and strange behavior; Bite marks and rodent droppings visible in engine bay
Codes mentioned: Check engine light
Repairs/costs cited: Harness replacement $3,500–$5,716; additional labor $2,200+ if engine removal or body lift required. Multiple owners report 3–14+ day wait for harness parts. Repair done twice in at least one case due to recurrence. Insurance covered some repairs less deductible; Toyota does not cover rodent damage under warranty.
Recalls/TSBs owners mention: Toyota does not cover rodent damage under warranty. Dealer-estimated and performed repairs. No recall issued despite multiple complaints citing soy-based coating as known attractant.
Door lock actuator failure
Driver and passenger side door lock actuators fail, preventing remote and manual locking/unlocking. Owners report this as a widespread issue on forums. Safety risk includes door unlocking when secured or remaining locked after accident, trapping occupant.
When: Within 55,000 miles; appears early in ownership
Symptoms owners cite: Door will not lock via remote key fob; Door will not lock manually from inside; Door remains unlocked when commanded to lock; Door will not unlock when commanded (possible post-accident trap scenario)
Repairs/costs cited: Replacement cost cited as $550–$800 per actuator. At least one owner replaced driver-side actuator out of pocket with no resolution, suggesting possible secondary electrical issue (BCM). No parts costs mentioned for warranty coverage.
Recalls/TSBs owners mention: No recall. Toyota charges owners $550–$800 per actuator for repair, which owners describe as exorbitant relative to part cost. No TSBs or extended warranty programs mentioned.
Seat warmer electrical fire hazard
Electrical wiring near seat warmer switch overheats and produces burning electrical smoke with visible sparks, creating fire hazard. Occurred while driving on freeway; switch was off, indicating unintended activation or wiring fault.
When: Unknown mileage; occurred during normal driving
Symptoms owners cite: Burning electrical smell; Visible smoke from wiring near seat warmer switch; Passenger seat becoming hot; Electrical components on verge of catching fire
Repairs/costs cited: Not stated; vehicle pulled over before failure escalated.
Battery mount broken/loose, causing electrical dropout
Battery mount breaks or loses fasteners, allowing battery to shift and upper mount contact positive terminal. Causes intermittent power loss to radio, USB ports, blower motor, dash cluster while driving at highway speeds. Generates sparks when removed.
When: Unknown mileage; occurred during highway driving
Symptoms owners cite: Radio power loss; USB ports power loss; Blower motor power loss; Dash cluster power loss; Sparks from battery terminal contact
Repairs/costs cited: Owner removed loose mount using non-conductive tool to avoid spark injury. No professional repair cost cited.
Rear-view camera electrical failure
Rear-view camera loses power intermittently, causing display screen to go black. Owner notes similar complaints reported on RAV4.
When: Unknown mileage
Symptoms owners cite: Camera screen goes black; Camera cuts out during use
Synthesized from 17 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
Rodents chewed up wiring harness for fuel injector. Vehicle parked in encoded garage.
Bought a used 2016 4runner. Had it 3 weeks and a rodent chewed the wires on the main wiring harness. Toyota (that I have 2 warranties through) does not cover rodent damage even though the material that they use attracts rodents apparently from my research. I have $3500-$5500 in damage and my car has been at the dealership waiting for repair for 3 weeks now. The insurance company is fighting them…
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…
Had electrical trouble with your 2016 Toyota 4Runner?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the electrical problem on the 2016 Toyota 4Runner?
It's a meaningful issue. 17 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $850.
At what mileage does the electrical typically fail?
Across the 9 complaints that reported odometer mileage, most electrical failures cluster between 12,000 and 40,000 miles, with the median around 29,922. A quarter of owners report trouble before 12,000; a quarter make it past 40,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $850 for electrical repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to electrical?
No active recalls currently cover electrical issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2016/Toyota/4Runner.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.