Q&A

When both lights are on, it makes me think that a sensor common to both systems (like a speed sensor) has failed. It's best to have a shop scan for the trouble code(s) stored in memory.

Ditto answer 2

happened to me as well on my is300 ...it was a o2 sensor. whenever the check engine light comes on the traction control automaticly shuts off. hope that helps.

My is300 did the same thing and it started running about like a diesel. Well what it was was the head gasket went bad. It was leaking between the number 1 and number 2 cylinders. That's worst case scenario though.

I just had this happen. Had a check engionelight come on, replaced the O2 sensor. Light came back on, then trac light also came on. The dealer said that the trac light is almost always nothing other than a more urgent message to get your check engine light looked at. FYI, my second light was a misfire right after the O2 sensor was replaced, which can happen when the system is re-learning with the new sensor.

Cylinder misfire. Replace coil packs, wires & plugs & you'll be good to go.