Notes: Although it has a stellar record in terms of vehicle problems, initially the 4th generation (2003 - 2009) 4Runner didn't earn our top "Seal of Awesome" rating because it received poor crash test ratings for rear impacts. However it's proven to have one of the lowest driver death rates out of all vehicles (not just SUVs), so we've bumped it back up to our top award.


hardly worth mentioning
Crashes / Fires:
0 / 0
Injuries / Deaths:
0 / 0
Average Mileage:
56,432 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2003 Toyota 4Runner electrical problems

electrical problem

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2003 Toyota 4Runner Owner Comments

problem #6

Aug 052010


  • miles


My 2003 Toyota had emissions issues in that all four oxygen sensors would fail quickly. It took me two years and lots of money later to determine that the cause of this is because transmission fluid is wicking its way through the transmission solenoid harness all the way to the ECU and once there because of the way the ECU is mounted gets into all of the other wiring harnesses of just about every other sensor. I went to Toyota and the first technician never heard that happening before but another overheard our conversation and said "I bet you have a 4runner" so yeah its happened to others. They wanted nearly $4500 to fix the issue. New engine wiring harness $1500-$2000 and another $1000 for the labor and the rest of the estimate is for other parts not specified. Their solution is to cut the wire below the transmission wiring harness connector then splice and solder but I would have to replace nearly all the critical wiring in that car. I cant give an exact date on when it started going wrong but I can look at the service history on the Toyota owner's website and give you this timeline. 0-89,997 - no, issues with emissions or electrical systems. 89,997mi - 90K service done - transmission fluid change w/flush done at dealer. 98,152mi - car reporting lean codes, dealer replaces maf sensor. 100,117 - car reporting lean codes, dealer replaces O2 sensor and A/F sensor bank 2 position 1 & 2 105,312 - car reporting lean codes, dealer replaces bank 1 position 1 A/F sensor and maf sensor again. Total cost $798.76. There are more but I have character limits. I will say this though that the problem should have been obvious because you can clearly see the fluid when you unplug the O2 sensor from the harness but Toyota was content charging me $500-$700 every 10K miles without actually fixing it. Car still remained functional but ruined fuel economy.

- Cabot, AR, USA

problem #5

May 262015


  • 168,040 miles
Upon starting vehicle, gas gauge and tachometer did not work. Turned ignition off then restarted and gas gauge fluctuated and finally responded, but no response from tachometer. After driving vehicle with air on, stopped at store then started vehicle and all gauges worked. This has happened quite often since it is getting warm. I have read blogs where other owners of the sport model are experiencing the same issue with the cluster failing. Some have tried to get repaired and that's a 50/50 shot. The only way to resolve is to replace cluster at $300 used without labor and an extra fee of $100 to calibrate mileage. Toyota is aware of issue, but fails to respond.

- Arlington, TX, USA

problem #4

Feb 282012

4Runner 8-cyl

  • 50,000 miles
On approximately February 28, 2012, the ABS/trac control/vsc lights came on and remained lit on my 2003 Toyota 4runner. I called the dealership and they said to bring it in right away. They diagnosed the car and came up with "no sensor reading?. it cost me $150 for the diagnostic test. I picked up the car and a few weeks later I brought it back for the same problem. The computer then indicated that there was a faulty O2 sensor which they replaced my cost was over $650. The next week the lights came on again. The dealership kept the car for a few days but later reported that they could not duplicate the problem. They told me that I should wait until it got worse and bring it back. I suffered with this problem for months. I say suffered because when I was in park and these lights came on, I could not shift out of park. The lights would eventually go away and allow me to drive. On 8/24 the problem became worse. I could not shift my car out of park for more than 15 minutes on over 10 different occasions. The warning lights remained lit almost constantly over 3 days. When I called to return the car to the dealership on 8/27, the service person said that she thought there was a recall associated with that issue, but then told me that there was not. Later that day, they called and said that they again could not replicate the problem. After a quick internet search, it seems that many people have had the same experience that I have had on various Toyota vehicles. I feel an investigation is appropriate in this instance.

- Baltimore, MD, USA

problem #3

Dec 012004

4Runner 6-cyl

  • 12,000 miles


The vehicle would rev itself up to a high RPM, from a stopped position when I stepped on the gas the vehicle would go in reverse. The dealership eventually replaced the transmission only after the manager borrowed it overnight and experienced it himself, but I have noticed the problem beginning again. Another problem is the radiator leaking and needed to be replaced (I was told it had the wrong kind of antifreeze; it was green and it needs a red kind"?"). when replacing this I was notified that my front brakes were paper thin and needed to be replaced this repair cost me almost $2000. Another problem is the rear window trim has shrunk. I also had the sunroof replaced after owning the vehicle less than two years. The brake light on the rear hatch does not work as well as the rear wipers (also when I hooked a trailer to it the electrical system seems to be messed up because the trailer lights will not work; went to autozone and tested the trailer and it is fine). The vehicle is starting to act funny again, the engine revs itself to high rpms (this is not the automatic tranny because it happens when it idles as well). The last incident was when I pulled out from a street parking spot and as soon as I put it in drive the vehicle stalled and we lost all power, when I pressed the gas pedal it was as if it was in neutral yet I triple checked and it was in drive. All of the sudden it acted normal and drove about 10 feet then it happened all over again. I also have the rotten egg smell (sulfur?) which is sporadic. Of course the dealer always says they can find nothing wrong, nothing is coming up on the computer. Luckily no injuries have occurred as of yet but I feel it is only a matter of time before I am on the highway and it decides to play these games. Very disappointed in quality of this vehicle, especially since I purchased it because of the reputation.

- Colorado Springs, CO, USA

problem #2

Jan 162005


  • 15,000 miles
I purchased a brand new 2003 Toyota 4runner in May 2003. In one cold morning of Jan. 2005, I was driving it in highway that was still covered with some snow. All of sudden, an engine check light on the dashboard was automatically turned on, followed by vsc lights, indicating that a vehicle skid control function was automatically turned off. At that point, I could not drive the car beyond 50 mph, no matter how hard or frequently I pushed the accelerator pedal. I pulled over, restarted, and re-entered the highway but had the same results. I managed to drive the car to a dealer for inspection the same day. The dealer could not find a cause and simply reset the computer controller. This seemed to have resolved the problem at that time. However, the engine check and vsc light issues resurfaced about two years later. The difference this time was that there was no acceleration issue. No inspection was made. The dashboard lights were automatically turned off after driving for about a month. In Jan. 2010, those lights reappeared and have remained turned on. No impact on acceleration has been observed.

- Jersey City, NJ, USA

problem #1

Oct 032009


  • 93,555 miles
After replacing an oxygen sensor several times, the dealership finally discovered the root of the problem that is making the oxygen sensor and traction control circuit short out. The air divertor flap inside the HVAC box under the dash had grease applied to the flap hinges in the factory. Directly below the flap is a wiring harness which drops down from the HVAC box and plug into the ECU. Over time the grease has traveled down through the wiring harness to the electrical connection plug into the ECU causing various circuits to short. No damage at present, however various safety circuits such as traction control are being affected. Furthermore, as oil is combustible, an interior fire could result from the oil penetrating the 12 volt electrical connection point on the ECU. This issue/ problem should be considered hazardous and should be a recall to replace the wiring harness and ECU as well as clean the grease out of the HVAC box.

- Chapin, SC, USA

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