Lexus GS exhaust back pressure sensor issue

I had similar symptoms on my GS. Warning light and smoke. It was indeed the exhaust back pressure sensor. Are you monitoring the sensor's readings? What's the manifold absolute pressure looking like?

Thanks for the quick reply! The MAP seems within spec, but the back pressure sensor readings are erratic, spiking intermittently. Did you replace the sensor yourself, or did you take it to a shop? And did that solve your problem?

Definitely sounds like the sensor. Replacing it fixed the issue completely. Given the location and fiddly nature of some of the vacuum lines down there, I'd suggest having a qualified mechanic do it. It's doable yourself, but a pain. Best to go to the workshop.

Appreciate the advice. Took it to a local shop, just as you suggested. The exhaust back pressure sensor was indeed faulty. Total repair cost was 245€. All clear now.