[Burple]

My 01 PT Cruiser suddenly started exhibiting detonation under load w/no codes present or past. Replaced knock sensor and tried higher octane gas, started in middle of tank, no help. Any ideas are welcome.
THANX, Roger

 

[Burple]

Not everything will or can set a fault code. That is why the troubleshooting procedure book has a 'no code' section.
Common causes are advanced timing, high combustion chamber pressures/temperatures and lean mixtures.

Where can I reference the book you referred to? Timing in the ecm and possible lean mixtures were my thoughts as well but feel the need to confirm source before throwing more parts at it. I am considering a scan tool w/live data but am unsure what I am looking at. Currently considering a "FIXD", any suggestions?

 

[Burple]

Thanks, after more research and head scratching, I've come to agree w/EGR diagnosis and have one ordered. This is my newest vehicle by far, so my preferred shop does not have needed live data scanner. Really not trusting of most other local shops, especially local Dodge and Chrysler dealers. Will report back w/results. Thanks to all who answered.