rmloan

Hello, I'm new to the forum and hope this ends up on the ES300 Forum. I recently had the check engine light. The mechanic ran the diagnostic which showed P0441, P0442, P0446. I understand what I need to do to troubleshoot those diagnostic codes. Here's my question: The mechanic ran a "Smoke Test" on the evap system. It came with a $90 charge. Was the test necessary? Thanks

Rollin'ES3

Well the codes you mentioned are evap leak codes within the evap system.

The smoke test basically goes through a vacuum hose or whatever, and sends smoke into the "leak free" evap system. Then you wait and see where the smoke leaks from, and that will be the culprit.

I'd say its a necessary first step into diagnosing the problem.

GEORGE_JET

If you have a evap leak, the first logical thing to test is the gas cap (highest failure rate), and then you smoke it. So the mechanic was taking logical steps.