Toyota 4Runner owners have reported 3 problems related to o2 sensor (under the electrical system category).
Cel vscoff vsc trac. Had it checked, was told #6 cylinder plug or coil, replaced coil and all spark plugs . Cel light went off the next day but came back on following day. Noticed a sound of water moving in a pipe or what sounded like in a pipe behind dash for a second or so. Was idling and running rough while driving, engine was shaking. Went on some web sites read some comments from other owners ,bad head gasket. 4runner has been well taken care of never abused only 8 years old, normal miles I think, not very happy with this. Bad design of cylinder head. I own a 94 4by 4 pick up bought new 250,000 miles lot a original parts still on truck runs very well except for bad rot on chassis happy with truck was very good to me as was I to it. I also have a 01 tundra sr5 bought 2 years ago with 132,000 runs well, 02 sensor replaced pass. Front went well but now have to replace pass. Rear impossible since rot will not permit me to have to replace cat converter, noticed lots of rot on frame as well as other areas under truck. Have loved Toyotas till now only had good things to say about them, starting to have second thoughts.
See all problems of the 2006 Toyota 4Runner.
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.
See all problems of the 2003 Toyota 4Runner.
While driving, the cel (check engine light) came on and the vsc trac and vsc off lights came on as well. Apparently Toyota disables vsc when the cel is triggered. In my case, the 2 times it has occurred has been due to emissions related failures (1st time the cat failed, 2nd time one of the O2 sensors failed). In the 1st case, I immediately took the vehicle to the dealership as I was approaching the end of the emissions warranty. They made the repairs and cleared all the codes so wasn't aware that the vsc system was actually disabled. The 2nd time (O2 failure) I replaced the failed O2 sensor, the cel has cleared, however the vsc lights are still on and vsc is disabled. I have serious concerns that Toyota disables key safety systems due to emissions related failures especially given the inherent stability problems with SUV's. If I'm on a trip with my family and an O2 sensor fails, or a catalytic converter fails, or the gas cap fails, key safety systems that help keep my family and I safe should not be disabled! I think this deserves an investigation.
See all problems of the 2004 Toyota 4Runner.