'02 4Runner sensors won't reset

[Punka]

Hello, I live in NY State and I recently had to replace my car battery and have my Evap system sensor. Apparently all my sensors for the system cycled and are ok EXCEPT for my Evap system and second O2 sensor. My mechanic said it is running a bit rich, about .7 but I do not have a check engine light on. Due to state regulations I can't pass inspection if the system doesn't reset. I have put 800 miles on the truck since my first system cycle/reset.

He is recommending I replace my Catalytic Converter in order to fix the problem. I have already changed my o2 sensors LAST year for a check engine light and my truck passed emissions with no problem. Now he replaced my Evap sensor in the rear of the car. I don't want to replace my Cat if that DEFINITELY is not the problem! :redbrick:

I took it to another shop and he made sure everything was connected correctly and reset everything to see if it was a computer glitch. It's been almost 200 miles and they are still not going green. Does anyone have any suggestions or a similar problem they have over come?

Thank you!
- Joe from NY

 

[TheDurk]

My truck went four months with a Catalyst System Not Ready Indication. It was no big deal as I'm not due for inspection until 2013 but it was a head scratcher. There was no MIL and no DTC codes stored. I wouldn't have noticed except I got a tablet for Xmas and I was playing with the Torque App.

Finally, in April, it set both a P0420 (Rear O2/Cat) and P0171(System too Lean). Huh? Anyway, I cleaned the MAF because of the P0171 and reset. System went full Ready on all parameters within half a tank and all green. That was the beginning of summer and no codes since. I clean my MAF every 30K when I do my plugs, and it had been only 17K since the last cleaning.

Anyway, I suggest a MAF and throttle body cleaning anytime the exhaust system monitoring is screwing up.

I got nothing for you on the EVAP; mine has never triggered.

 

[BlackCat914]

replacing a convertor will not solve it, it's a readiness issue, not a part failure issue. The system is designed to run certain tests when certain parameters are met. For example, the car might run the Catalyst system test when you're doing 70mph for 13 minutes after the 3rd key cycle and the TCM see's the torque converter lock up. They're weird like that.

 

[Punka]

Thanks for the responses. Isn't it a little tricky cleaning out the Mass Air Flow system yourself? I've read people taking them apart and messing up one of the very expensive sensors associated with the MAF. Let alone it being a little tough to get to. I know the throttle body cleaning is relatively easy with some CRC spray... I'll look around the forum for some successful MAF cleanings before I go at it.