Hey guys. I have a 2000 Cherokee and I recently had the check engine light come on. Long story short, it appears that both O2 sensors are shot (P0132, P0135, P0138, P0141).
Here's the kicker...my Jeep runs fine and my fuel economy has actually gotten BETTER since the light came on. If I have to do something that requires disconnecting the battery it runs rough for a few days but then smooths out. I guess my question is this...since I'm getting increased fuel mileage and everything seems to be running fine, if there any real reason to replace the sensors?
Thanks to anyone that reads or responds to this post.
You have two codes that are related to the HEATER circuit of both your upstream and downstream oxygen sensors.
It is possible, but it is highly unlikely that both sensors went bad at the exact same time.
What is more likely is that you blew the fuse to the heater circuit. The fuse for this is located inside of the power distribution center (the black box under the hood on the passenger side). I'm not sure of the exact location, but somewhere in the 10-17 slot range. It definitely is a 15 amp mini fuse though. Jeep did a disservice by not labeling the PDC cover with all of the pertinent information. So inspect or better yet, put a meter on all of those mini-fuses to verify their condition.
You MUST verify this fuse before condemning your oxygen sensors. It very well could be the root cause, and is not that uncommon on the 97-01 4.0 engine; I answer threads about this every month or so, and just helped a guy with this exact same problem on another XJ forum. I hope this is your problem.
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche Without "data", all you have is an opinion!
I've always been a "the Glass is twice as big as it needs to be" person myself.....
Since time is really just a measurement from one event to another, it's individualistically relative (we all view and experience time differently). So if there's no "good" or "bad" events to focus on time seems to stand still.
I've been watching too much Into the Wormhole....
__________________ Scott-Crawlorado Native
I have an addiction.....
*00' XJ_T-n-T Y-Link/6" RE_OME's_33" KM2's
Tera 4:1 / 4:56's_Elec. Locked D44
**84' CJ7 4"BDS 33's
***02 WJ Overland
Do as TJwalker said, clear the codes...and see what happens.
How does one go about clearing the codes?
Lately, I've been getting an intermittent Check Engine light. Comes on for while, then goes away. I too was thinking one of my sensors is going out. But I thought that once the light comes on, it basically stays on for x number of starter cycles.
Just puttin this out there... my 2000 sport had pinched wires in the o2 sensor harness that runs over the top of the tranny. The guy that changed out my engine found them and also found wires with bad insulation running along the the firewall. Some techs have figured out how to cheat the computer connections so they read good sensors... it's easier than chasing down bad wires. Best of luck to you!
Kinda sarcastic replies for needing our help little buddy.
The answers I was replying to weren't thought out very well. Asking if the check engine light is still on is silly considering there are people advising me to clear the code and "see what happens"...the logic being that if the check engine light is off, things are OK. So if the check engine light was off I wouldn't be asking about it, right?
Same for the reply about O2 sensors ruining your gas mileage. I mentioned in my post that my fuel economy had actually gotten BETTER...so what do I say to someone who declares something to be the exact opposite of what I have said (and can prove) to be the case?