MileageCurve What breaks, and at what mileage

Toyota 4Runner 2003–2009

4th generation · N210 · 3,009 complaints, 2,123 with mileage

Owners filed 3,009 complaints with NHTSA about the 2003–2009 Toyota 4Runner, and 2,123 of them record the mileage at which the failure happened. That is enough to show not just what fails, but when.

58% of failures occur beyond 100,000 miles — a wear pattern. The car generally reaches substantial mileage before trouble starts.

The most-reported areas are body structure (32.5% of complaints, typically around 131,000 miles), problems owners could not categorise (12.9% of complaints, typically around 139,500 miles), the suspension (12.8% of complaints, typically around 134,000 miles).

7 recall campaigns cover this generation.

When failures happen

0–5k: 93 complaints (4.4%)0–5k5–10k: 30 complaints (1.4%)10–20k: 69 complaints (3.3%)10–20k20–30k: 67 complaints (3.2%)30–40k: 51 complaints (2.4%)30–40k40–50k: 75 complaints (3.5%)50–60k: 87 complaints (4.1%)50–60k60–70k: 84 complaints (4.0%)70–80k: 102 complaints (4.8%)70–80k80–90k: 110 complaints (5.2%)90–100k: 115 complaints (5.4%)90–100k100–120k: 229 complaints (10.8%)120–140k: 276 complaints (13.0%)120–140k140–160k: 246 complaints (11.6%)160–200k: 328 complaints (15.4%)160–200k200k+: 161 complaints (7.6%)3280

10% of failures occur by 21,000 miles · a quarter by 66,000 · median 115,000 · three quarters by 155,000 · 90% by 190,000. Based on 2,123 complaints that record mileage.

What fails, and when

SystemComplaintsShareTypical mileageMiddle half
Structure97932.5%131,00095,000–165,000
Unknown Or Other38712.9%139,500104,000–165,000
Suspension38412.8%134,00095,000–172,934
Service Brakes1635.4%117,00086,000–160,000
Power Train1525.1%59,00016,000–108,000
Vehicle Speed Control1364.5%53,50023,377–90,000
Steering1234.1%100,00065,000–151,000
Air Bags1013.4%87,00052,000–138,000
Service Brakes, Hydraulic822.7%50,00023,000–85,000
Electrical System782.6%111,50050,000–160,000

By model year

YearComplaintsWith mileage
2003718511
2004847570
2005553386
2006520375
2007204147
2008134103
20093331

Which systems, and when

Complaints about this generation are not spread evenly across the vehicle, and the systems that generate the most of them do not all fail at the same point in a car's life. The median failure across all systems here is 115,000 miles; the figures below show which parts of the car run ahead of that and which run behind.

Body structure accounts for 32.5% of complaints (979 reports, 651 of them with a mileage figure), with a median of 131,000 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 95,000 and 165,000 miles.

A single system taking 32.5% of all complaints is a concentration worth noting. It means that for this generation, most of what owners reported came back to one area of the car rather than being distributed across many small faults.

Problems owners could not categorise accounts for 12.9% of complaints (387 reports, 230 of them with a mileage figure), with a median of 139,500 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 104,000 and 165,000 miles.

The suspension accounts for 12.8% of complaints (384 reports, 246 of them with a mileage figure), with a median of 134,000 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 95,000 and 172,934 miles.

The brakes account for 5.4% of complaints (163 reports, 129 of them with a mileage figure), with a median of 117,000 miles, close to the vehicle's overall pattern. The middle half of these reports falls between 86,000 and 160,000 miles.

The transmission and driveline accounts for 5.1% of complaints (152 reports, 129 of them with a mileage figure), and it fails early — a median of 59,000 miles, well before the vehicle's overall median. Failures clustered this far below the rest of the car usually point to a design or manufacturing problem rather than wear, because wear does not selectively target one system on low-mileage examples. The middle half of these reports falls between 16,000 and 108,000 miles.

Throttle and speed control accounts for 4.5% of complaints (136 reports, 115 of them with a mileage figure), and it fails early — a median of 53,500 miles, well before the vehicle's overall median. Failures clustered this far below the rest of the car usually point to a design or manufacturing problem rather than wear, because wear does not selectively target one system on low-mileage examples. The middle half of these reports falls between 23,377 and 90,000 miles.

Differences between model years

Within this generation, complaint volume is not constant across model years. The 2004 model year drew the most — 847 complaints — while 2009 drew the fewest at 33. The median year sits at 520.

Recalls and what they cover

NHTSA records 7 recall campaigns covering vehicles in this generation. A recall means the manufacturer or the regulator concluded there was a safety defect or a standard was not met, and that a free remedy is owed to owners — including second and later owners.

The campaigns cluster around seats (3), equipment (2), the airbag system (1). Repeated recalls against the same area of the car generally mean the first remedy did not fully resolve the underlying problem.

Recall status is specific to the individual vehicle, not the model. Checking a VIN against NHTSA's lookup is free and takes under a minute, and it is the only way to know whether a particular car has had the work done.

Reported severity

Of the 3,009 complaints filed against this generation, 146 reported a crash; 19 reported a fire; 105 reported an injury. Crash-involved reports represent 4.9% of the total.

These are owner-reported outcomes, not verified investigations, and they are not adjusted for how many of these vehicles are on the road. They are included because the distinction between a fault that strands a car and a fault that causes a collision is the one that matters most, and it is not visible in a complaint count alone.

What this means if you are buying one

For a buyer, a late-failure pattern shifts the question from whether to when. 58% of reported failures occur beyond 100,000 miles, so an example approaching that figure is approaching the range where other owners started reporting problems. The middle half of all failures falls between 66,000 and 155,000 miles.

On inspection, body structure and problems owners could not categorise are where this generation's reports concentrate, so those are the areas worth a specific look. Body structure in particular shows a median failure mileage of 131,000, which gives a concrete number to compare against the odometer of any car you are considering.

None of this is a substitute for a pre-purchase inspection on the individual car. Aggregate patterns describe a population; the example in front of you has its own history.

Documented problems

Structure — frame corrosion 2003-2009 (salt-belt vehicles; early years most affected)

Severe frame corrosion in salt-exposed regions that can compromise structural integrity. Toyota ran inspection campaigns for early 4th-generation vehicles and offered frame replacement or vehicle buyback for qualifying trucks.

Recalls (7)

CampaignDateComponent
16V0650002016-12-01Air Bags:Side/Window
16V3960002016-07-14Seats:Front Assembly:Seat Heater/Cooler
14V7430002015-01-29Seats:Front Assembly:Seat Heater/Cooler
13V0140002013-03-21Seats
11V1130002011-04-13Vehicle Speed Control:Accelerator Pedal
10V0360002010-05-27Equipment:Other:Labels
10V0350002010-05-27Equipment:Other:Labels

What owners reported

2003 · 1 miles · Structure
CHASSIS/FRAME ON 4TH GENERATION 4RUNNERS HAVE A SEVERE RUST PROBLEM. MANY ARE DOCUMENTED & DISCUSSED AT HTTP://WWW.TOYOTA-4RUNNER.ORG/4TH-GEN-T4RS. SIMILAR TRUCKS IN TOYOTA'S PRODUCT LINE QUALIFIED FOR FRAME REPLACEMENT BUT THE 4RUNNER WAS IGNORED. THE REST OF THE TRUCK IS 100% RUST FREE EXCEPT FOR THE FRAME. RECENTLY HAD A BODY SHOP LOOK AT THE FRAME - WAS DESCRIBED AS "TOO RUSTY TO WELD ONT…
2003 · 2 miles · Service Brakes
WHILE PULLING INTO A GROCERY STORE PARKING LOT, ALOUD CABIN ALARM SOUND AND ABS, VSC AND TRAC AND BRAKE WARNING LIGHTS ON THE DASH CAME ON. MY VEHICLE SEEMED TO STOP OK SO WE DID OUR SHOPPING, WHEN WE STARTED THE CAR IT STILL HAD THE LIGHTS LIT UP AND BRAKED OK. WE WERE CLOSE TO HOME SO I DROVE SLOWLY TRYING TO GET THERE ABOUT HALF WAY HOME I APPLIED THE BRAKES AND THE PEDAL WAS HARD AS A ROCK AND…
2003 · 40 miles · Structure
WE HAD JUST BOUGHT THE VEHICLE WHEN THE REAR END BEGAN SWAYING FROM SIDE TO SIDE AND WE TOOK IT TO THE MECHANIC AT TOYOTA AND WAS TOLD THAT THE WHOLE FRAME WAS RUSTED OUT AND WAS TO DANGEROUS TO DRIVE BUT THEY COULD NOT HELP US. THE SAME FRAME WAS ON THE OTHER 3 MAKES AND WAS RECALLED AND THAT OURS NEEDS TO BE RECALLED. THEY ALL KNOW IT NEEDS TO BE RECALLED AND I WISH THEY WOULD JUST DO IT BECAUS…
2003 · 217 miles · Structure
I HAVE HAD THIS VEHICLE FOR MANY YEARS AND I "KNOW" IT. I NOTICED THAT HE STEERING WHEEL HAD A VIBRATION ALBEIT SLIGHT, THIS WAS SOMETHING NEW AS WELL AS A NOISE I COULD HEAR UNDER THE CAR. I BROUGHT IT HOME COMPLAINED TO MY HUSBAND - HE LOOKED UNDER THE CAR & WAS APPALLED - THE FRAME IS SO RUSTED HE WAS ABLE TO STICK HIS FINGER THROUGH THE FAILING FRAME! I AM AFRAID THIS VEHICLE WILL KILL ME! W…

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