Check Engine Light Expert Please...Lol

NYSpeed Automotive
1

I have the weirdest check engine light maybe someone on the board can help me…

the car is a 2004 Jeep Liberty Sport, 3.7L, Automatic
I got the car with no check engine light but then after driving 30miles. it came on.

I ran a scan and what it pulled was p0137, so then i looked online to see whats this code meant and it was for the o2 sensor after the cat on the drive side. then a day later another code seemed to appear p0142. which has soemthing to deal with the cat itself. so i assumed that the o2 sensor is bad and causing these two code to be on.

I brought a bosch o2 sensor. disconnected the battery wihile i installed it. after i installed it the check engine light turn off for 20 miles then it came back on…I scanned it again and the scanner said “PASS” with no codes…while the check engine light was still on…

So. I just erase the “no code” and the check engine light went off for 20 miles it went back on.

I scanned it again and NO CODE were found but the check engine light is still ON!!

Im Stumped beyond belief…

This is my conclusion:

  1. on the jeep forums they said look for a o2 sensor fuse…i have no clue where it is.
    2.the ECU is bad.
2

yes there is a fuse for the 02 sensor. And it is super common for chrysler pcm’s to take a dump. The pcm’s are not sealed very well and usually installed in bad areas. They become very corroded internally causing all sorts of grounding issues. Also installing a bosch 02 sensor on chrysler products does not seem to yield good results.

Are you reading the codes with the engine running or KOEO? KOEO is the way to go.

3

i dont know what KOEO is but i pulled the code non-running. with a actron from auto zone.

No the p0137 code is gone and i have a p0420 code.
should i use a non-fouler mod and call it a done deal!?

4

Sounds like you’re still chasing a cat problem.

Pretty straight forward.

5

find someone with a modis so you can better diagnose itand possibly get a history code. autozone scanners are shit i have a decent snapon scanner if you want pm me and i can scan it for ya, i can view the live data and check to see what o2,s are working properly

6

word, find some one who can watch live data, i have a genisys if your near seiferts at all.

7

any real scan tool with mopar software will yield more useful results, and as stated chrysler computers have very bad tendencies to leak factory smoke, rendering them useless.

8

$5 Non-Fouler Kit and no more check engine light and get 4mpg+ more then previously :slight_smile: lol

it was a combination with the o2 sensor being indeed bad and someone gutted out the converter…so the previous o2 sensor got fried. so instead of getting a $200 cat i went to the auto store picked up the non fouler kit, drilled out one of them with 1/2 in drill bit, pop the o2 sensor in like this

Non-drilled out fouler adapter then 1/2in drilled out fouler adapter and then the O2 sensor.
Has not got a check engine light and the car runs 100x better.