i think my ecu is bad in my 99 se cali spec. its been rough idling for a while and the other day my brother went to check to see if any hidden codes (no cel light) and then the next day the cel came on and no more rough idle. i bring it to 3 different autozones and the scanners wont read. scanner says like unable to read. could my ecu be gone? or what else? i value all your opinions. thanks!!!

 

I've personally never heard of an ecu going bad on a max. Plus rough idle although possibly caused by wrong reading in your ecu, is probably because of bad, plugs, coils or the need to clean out your throttle body. I'd go with those things first (which i have to do to my own max soon btw) then if you still have the same problems, i'd worry about the ECU. As a side note i'd check the codes manually (its in the faq's) if you don't know how. That way you can tell if its really your ecu thats unreadable, or if their scanners just don't want to read you ecu for some reason (broken pins on the connection or something).

 

all the coils, plugs,tb cleaning all maintenance (major/minor) is done. ever since cel came on the other day i have had normal idle. so is it the ecu?

 

I don't see how getting a code can make idle better, but i'd definitely use the screw driver method and check the code, it may answer your question. If anything you'll at least have a better idea of whats going on. After checking the codes you can reset the ecu, and after a few miles of driving it should readjust (i'd say about 50 miles or less). When u first reset the ecu you might have a slightly rough idle but it should even out, if it doesn't then i'd say it might just be your ecu.

 

I had the same problem w/the ecu. It wouldn't read w/a generic scanner. Or if it did read, it'd say "no codes".
1 day, I made it link for 30sec, then cancelled it. I finally got a code! So maybe tell the autzone person to cancel the link after 30sec, or 1min.
btw, my code was for camshaft position sensor.
Jae