So... i was getting the P0455 code, and one of the easy/cheap fixes was replacing the EVAP return line. So i did that. Today, engine light is back on. Now it is throwing both the P0455 and P0175. So im guessing the line wasnt the entire issue (it DID have a obvious hole in it) and i have to check other points in the EVAP system. All well n good but now im at a loss with why the P0175 all of a sudden popped on. It seems replacing the EVAP line made it worse, which probably isnt directly true. But what do you guys think could have caused the 175 code to pop up after i replaced that line? Or is is a coincidence? I did check the codes as soon as i got back to the house, but i dont think that has anything to do with it. I am learning as i go here, so i will be looking up how to fix the P0175 code.

 

In general, its better that you provide the code meaning which is

OBD2 code P0175 means that the air-to-fuel ratio in your engine is off, with more fuel in the mix than there should be123. This can decrease your fuel economy, increase your emission, and cause internal engine damage if not fixed promptly1. The code reports that an oxygen sensor located in bank 2 has detected a very high

so it may be you have a vacuum leak, faulty Evap component or O2 sensor, or exhaust leak etc etc

I would use my OBD2 live data to check these parameters, Vacuum, O2 function, ST fuel trim

 

Ah yes my apologies, i figured most would know the code meanings if they were willing to help, but noted for the future!

i am pretty sure there is an exhaust leak somewhere. i can hear an almost fluttering air sound toward the front that doesnt sound like something that should be there. i am hoping its not the exhuast manifold cuz thats a bit of work i dont feel like getting into right now...but if it is, i gotta do it. There is a hole in the muffler as well, very small, but there, but it was like that when i got it and there were no codes when i got it. I dont THINK the codes were cleared when i got it, but i dont know for sure. I have a new muffler and tailpipe to install just havent gotten to it cuz i need to get the dang old rusted bolts off or cut it. I took it to the store and when i got back i checked for codes again and now both banks have codes. (P0172 and P0175) I will do the live check tomorrow if it doesnt rain. thanks! Again still learning about a lot of this stuff, and i appreciate everyones help thus far! I just am itchin' to get these codes cleared so i can get it inspected and actually do some real driving with it.

 

So a buddy of mine said that an EVAP issue could cause the P0172/P0175 (system to rich bank 1& 2 respectively) codes. These popped up after i changed the EVAP line from the tank to the box under the jeep. I replaced it with a rubber fuel line and a few suggested as it is cheap and wont rust again. After i drove it the codes popped up..so i checked the line and the hose was still on but seemed maybe a little loose on the tank end. So i loosened the clamp slid the hose on further, and retightened it until i couldn't pull the hose off. Codes are still there, but i am guessing they wont immediately go away and i may have to run the car a few cycles for them to clear. Do you guys think that could be the issue? I haven't had the chance to run the car a few cycles and its going to rain again tomorrow.

 

If you have a code reader it should have a Clear Codes option.

 

yes it does i did it once, by accident lol. But it takes a few running cycles for it to read codes again, so i was just asking if anyone thinks that line change could have been the issue, because the car has not been inspected yet (still have temp inspection that is expired) and i dont want to clear the codes again if i can avoid it because then i have to drive 50-100 miles before the DMV computer will read it as "ready" im already risking a ticket driving around with basically no inspection, so i am keeping the driving to a minimum and in low traffic areas.

 

I'm not understanding that logic but IIWM I'd clear the codes and reset the PCM. Having corrected the massive leak should now be causing MAP to report more air entering and PCM to dump more fuel. Let PCM relearn AFR.

 

From what i understand to reset the PCM i have to drive it no? If there is another way please let me know!

yessir, thats what i would think as well, assuming there isn't another leak somewhere. So, I just cleared the codes again(on purpose this time lol) . and i redid the back/fuel tank end of that EVAP line as originally i think i didnt get it on enough and the clamp wasnt tight enough so it may have still been leaking (hence the P0455 code showing still). I slid the line on 2" at least and retightened the clamp so i couldnt pull the line off. So, I have to drive it around and see if the CEL comes back on.

However i dunno why right after i switched the line initially, those 172 and 175 codes came up. Like you said, id guess that would put more air in the line not less. I would have expected the P0455 to come back on if i didnt clamp the line tight enough, and it did, but it also had the 172 and 175 codes it didn't have previously.

Keep in mind the car sat for at least 8 months, so im also assuming that now that its driving again stuff may rattle things loose or what have you.

So what im doing for now is im gonna drive it locally (hopefully i wont get a ticket for having no inspection) and then recheck the codes if the CEL comes back on which i suspect it will, but hopefully with only the 172/175 codes. If that happens i will change the sensors cuz who knows how old they are and they are a cheap replacement. then i'll take it from there i suppose.

If i am missing something please let me know, i am but a learner still!

 

From Dukie564 at NAXJA (hey, why do extra work if you don't have to):

 

this sounds like voodoo! haha thanks!

 

Well see what your fuel trims are before and after.

 

So i cleared the codes and did the voodoo (rest the PCM) lol Light came back on after a couple of local trips to Vet and the supermarket. But now only P0175 comes on. The P0172 and the P0455 so far are gone. So hopefully the hole in that EVAP line that i replaced was the P0455 culprit. If it stays this way i will change the sensors cuz i may as well do both.