One problem related to o2 sensor has been reported for the 2006 Toyota Sequoia. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Toyota Sequoia based on all problems reported for the 2006 Sequoia.
In March 2016, I had - for the first time - the vsc trac, vsc off, brake, and abs lights on instrument panel come on. . . All 4 on at once. Then again, today, I had the vsc trac, vsc off, and brake lights come on. A known issue for both Sequoia and tundra models, owners have tried to get a recall. Many thoughts online about what causes this; it appears it's a faulty skid control unit (ecu unit). Says the ecu will take the vehicle into a "safe" mode and limit output power and acceleration, until this is resolved. I experienced this today after the lights came on. Others online say might be a bad brake fluid sensor, brake pedal switch or oxygen sensor. However, overwhelmingly it seems to be a faulty ecu� and this is a very expensive electronic part ($2,300)!.