Lexus IS diesel check engine light and exhaust sensor

Hey, I have an IS too. I had similar symptoms a while back. The check engine light, power loss, and worse gas mileage all point to something in the exhaust system. Have you checked for any obvious leaks or damage there? The exhaust temperature sensor, also known as heat sensor or exhaust sensor, is an exhaust component monitored by the engine management system. If the sensor is faulty, or there is a leak, the car will be affected.

Thanks for the info. I haven't checked for leaks myself. Where exactly should I be looking in the exhaust system?

Honestly, unless you're comfortable working under the car, it's best left to a professional. Exhaust systems can get very hot and there might be dangerous gases. I'd suggest taking it to a workshop. They can do a proper inspection and pinpoint the exact issue. It’s most likely a leak somewhere near the exhaust sensor. Good luck!

Okay, thanks for the advice. I took it to a shop, and you were right, there was a leak in the exhaust system. They replaced a section and the exhaust temperature sensor. The total repair cost was 265€. Everything seems to be running smoothly now.