Lexus GS Hybrid Exhaust Leak

Rough running, check engine light, exhaust smell AND a leak? That’s quite the symphony of problems. The NOx sensors could be a culprit for sure, especially with the light and rough running. But an exhaust leak suggests something more mechanical. Have you checked the EGR valve or taken a look at the lambda sensor? What codes are popping up on the OBD reader?

Thanks for the reply. I don't have an OBD reader to check the codes myself. Where exactly would the lambda sensor be located, and could a defective one actually cause an exhaust leak, or am I dealing with two separate issues here?

Okay, without the codes, we're troubleshooting a bit in the dark. A faulty lambda (oxygen) sensor itself won't usually cause an exhaust leak, that's almost certainly a separate issue – cracked manifold, broken seal, that sort of thing. The lambda sensor is typically located in the exhaust system, before and/or after the catalytic converter. Given everything you're describing, honestly, best take it to a workshop before things get worse and more expensive.

Thanks for the helpful advice. Took it to the mechanic and you were right. Turns out the lambda sensor was defective AND there was a small exhaust leak. Repair cost me 375€ including parts and labor to fix the leak and replace the oxygen sensor.