Hello, would anyone know how to turn off the"Service Engine Soon" light? I have a 98 Silverado with a 5.7l(350) engine, I know what causes it to come on but I 'am sick of taking it to the dealer. Thank you........Ed
Uhhhh, then either tighten it correctly every time you fill up, or replace the gas cap if it's still leaking even with it tightened properly. Not rocket science.
Actually it does answer your question, and I didn't mean to sound condescending. Sorry. If your PCM is detetecting an evaporative emissions leak that is in fact being caused by the gas cap being loose or not sealing correctly, the SES light will remain on as long as the leak is present. To turn the light off, fix the problem that is causing it.
You can turn the light off with a scan tool by clearing the error code, or you can yank the fuse for the PCM for a few minutes to clear the memory that way. I would recommend using a scan tool as blanking the PCM will force it to re-learn your system parameters the next time you fire it up and it'll run like ass for a few minutes. BUT, it's just gunna come right back on so long as the problem persists. I believe the SES light stays on for evap. emmissions leaks for 40 duty cycles, and will self-reset (tuen off) if the problem is gone 40 cycles after the code was set.
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