The wiring harness to the rear ABS wheel sensor fails. This must be a common problem as many people have been looking for this part. A warning light appears on the dash, it also prevents the vehicle from being put into gear. You have to use the override switch to put it into gear.

- Clarkston, WA, USA

Traction control light came on, check engine light came on and vehicle would move only slowly. Turned car off and on several times, tried engaging 4 wheel drive and other drive functions, tried accelerating, but vehicle would only move slowly. After turning off and on one more time the vehicle drove as normal but all the warning lights stayed on. This happened in a parking lot while going slowly. Mechanic has indicated that this resulted from a failure of the air injection pump and air valve, which apparently for some reason turns off traction control. This is a common enough problem on Tundra and sequoias that there is an "extended warranty" offered on these vehicles. I do not know if the air injection pump and air valves on 4 runners are the same design or same model, but there are numerous complaints on the internet of the same problem for 4 runners as for Tundra.

- Hebron, CT, USA

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 Toyota till now only had good things to say about them, starting to have second thoughts.

- East Providence, RI, USA

2006 Toyota 4runner check engine light disables traction control and vehicle stability control when on. For instance the car needed a gas cap. So the check engine light came on as well as the traction control and vsc light. Icy conditions and having something such as this fail because of poor wiring could be very dangerous.

- Columbus, GA, USA