Ok, I know there are quite a few fellas on here that know about engines real well on here, need your expertise. I know the question might be vague, but just need some guidance. I have a 98 ES300 with about 140,000 miles on it and just recently installed a rebored throttle body. I cleaned out the ICV very well and the valve moved freely, all wires, hoses and connectors were put back to their respective places and drove like a charm for a week and now I have a CEL. I cleared it by removing the negative battery cable and then attached it back, then started the car and CEL was gone. I drove it again and came back on 6 hours later. I had this same issue before when I topped the gas off to much and I recently topped off again. Wondering if its my gas cap going bad, because this also happened at higher elevations too. All three of my air/fuel sensors were replaced 8 months ago. Passed smog back in April, but did notice I was one point below max for I believe carbon emissions, but not sure. So I'm wondering if it could be my Cat., it's the original Cat. I guess my question is, what are the common causes of CEL on a 3rd Gen ES? I think I might have to find a place to scan my car or just go and buy a scanner. Thanks for any help.

 

You really need to get the CEL number and bring it to us. I have a lot of speculations about what maybe occurring, but scanners are getting cheaper these days and it makes good sense to keep one around.

This is the latest one I keep in my RX, http://www.amazon.com/Autel-MaxiScan...6167754&sr=8-1

 

Thanks Lexmex. I figured I would probably have to buy a scanner, was trying to avoid it and seeing if Kragen or Autozone would scan the car and they both said it's illegal to do in Calif. Well, I reset my CEL and it hasnt come back on again. I did open and retighten my gas cap and cleaned out my MAF sensor and the CEL hasnt come back on. This is the scanner I was thinking of getting.

http://www.amazon.com/Equus-3100-Inn.../dp/B000EVWDAK

 

That's not bad.

What I ended up doing was getting the scanner I just mentioned previously and also this to hook up to my laptop, http://www.amazon.com/423000-ElmScan...6257949&sr=8-1

 

Go get it scanned by autozone, o'reilly, or pretty much any auto parts store. They will do it for free. Why spend $$ when you don't have to.

 

In California they have a problem there where they won't do it. I've heard of that.

 

For some reason their is a legality issue in Cali, when a parts store scan your car, but one guy at a Kragen store in a different city did scan it over the summer, so I'm going to go back there again tomorrow and see if they will scan it again. To update, drove my car yesterday and no CEL, but drove it today for about 40 minutes and the CEL came on again. I cleared it and turned the car on again and no CEL. I figure if its a true positive CEL, the CEL would come right back on once the engine started.

 

Its not necessarily true that if there is something defective that the CEL will come back on immediatley,once you clear it.

It all depends on the nature of the faulty and the faulty system involved. The emission control components, if defective will take a relatively long time for the CEL to come back on. In fact it first stores the code in memory without activating the CEL light, (This is called a PENDING code) and only after a few predetermined cycles, if the fault is still there will the CEL come on. If you had a scanner, it will tell you if there are any PENDING codes in Memory, and which ones

On the other hand, some codes cause the CEL to light up immediately. Loss of OIl pressure is one such example.

You definitely need a Code reader to get a picture as to what's going on. Otherwise you are working in the dark.

Phil

 

Thanks Phil, was just trying to avoid buying a scanner. Like I said earlier, I'm going to try this one auto parts store that did it over the summer and see if they will do it again, if not I'm buying a scanner thru Amazon.com. I'm just hoping its nothing major, the car still runs like a charm. Just hate seeing the CEL on. Thanks again.