My Check engine soon light came on recently. I took it to autozone and the code told us to change out the O2 sensor after the carborator, downstream. Very easy change but I reset the computer and the light came back on. I am going back to Autozone to have them recheck the light but is anyone else having this issue....

I have the same problem 2 days ago.I have a 1/4 tank of gas and i fill it up.Suddenly it start choking when i press the gas pedal then later that afternoon the check engine light came on the whole night.But next mornning it was okay and running excellent.since then the light wont came on anymore.I was thinking I have a water moisture on the gas tank.because of the sudden changes of the weather temp here.

Similiar problem here....I took it to the dealership and they said it is a known problem. There is something in the ECU that is set incorrectly, and they had to reset everything. I had to leave the SUV there a full day while they reset everything and tested out.

The light hasn't come on since. I noticed no difference in vehicle performance, no noises, anything.

"Similiar problem here....I took it to the dealership and they said it is a known problem. There is something in the ECU that is set incorrectly, and they had to reset everything. I had to leave the SUV there a full day while they reset everything and tested out."

Did you change out the Sensor? How many miles were on it?

Endeavors dont have carburetors. There are four 02 sensors on it.The code must be cleared after making repairs. The 02 sensors are covered under the emission warranty. Also they require premium fuel and the gas cap must be tight or the light can come on.

The error code read that the O2 sensor bank 1 sensor 2 was faulty. This is the O2 sensor in the rear (closest to the cab) at the top. The malfunction was actually in the heater portion of the sensor. Holler Mitsubishi was very helpful however DON MEALEYS MITSUBISHI SUCKS and they were very unwilling to help at all!!!! Problem solved.

I to was told this is a known issue and that the mitsubishi engineers were writing a updated firmware for the computer but its been 6 months now and they still havent made the flash...when the "service engine soon" light comes on i can tell a noticeable differnece in the response of the vehicle acceleration and the shifting seems off, and the dealer ship has already replaced sencors and reprogrammed the computer a few times but the problem still exists i now feel like im being blown off and fear mitsubishi is just going to ignore this problem until the warranty expires and then claim stupidity. beleive me we are not the only ones with this problem in my area alone i have met several other owners of the endeavor and they report the same thing i fear mitsubishi is dropped the ball on this issue but i will still continue to pressure them if that dosent work i have already spoke to the local people around here that have the same problem and we are considering seeking legal help anyone else with this problem should do as i am and start applying pressure to mitsubishi on this one ...keep in mind mitsubishi is suffering finacial problems due to warranty issues involving poor quality of there engines which has just started over the past 2yrs all the other mitsubishi's i owned were wonderful vehicles and now i fear i purchased a mechanical nightmare

My dealer changed the sensor and solved the problem.

solved the problem for me too for about 2 1/2 months but now its back tonight i took it to mitsubishi dealer ship and they have it once again when i called mitsubishi motors they blew me off but i think the dealer ship is aware im not going to back off and has now are going to put pressure on mitsubishi to write the firmware flash in a timely manner

I found this http://www.mitsubishitechinfo.com/epacarb/PCMUpdates.pdf I think it can help when talkning to your dealers.

You know tell them what & how to do it - it has worked for me.

I just took mine in for a Service Engine light and it took them twice to fix it but they ended up replacing my Purge Valve and now everything is fine. I also learned there is a Parking Brake recall on mine which is a 2004. Something you all may want to look into. Just a heads up!

I just took my 2005 endeavor in for the same problem. It only has 5,000 miles and the service engine soon light came on. I took it to the dealer and they said that I shouldn't use costco gas or low grade gas like from costco or sams club. That sounds like a bunch of bull! Plus I don't use low grade gas! What should I do?! I don't want to have problems with my brand new car! are you all having the same problem with the 2005 endeavor or was it another year? If it is in the 2005 it sounds like a manufacture problem. Any advise?

I have the same problem NOW with my 2003 GTS. but besides ENGINE SERVICE SOON my RPM going up and down on a (P) speed. any sugestions.?

I have a repeat problem. Today check engine light came back upon a cold start.
The light came first time when I was driving in Cape Cod area two years ago and called a local dealership where I was told to open and properly close the fuel tank cap. This helped for a week or so.
My dealership (North Toronto Mitsubishi) attempted to troubleshoot this problem. The mileage was 35 K at that time.
I needed to come back 4 (!) times with the light going off before they were finally able to fix that (every time the onboard computer was reset).
It was the catalytic converter, 3 other times they replaced oxygen sensors.
Apparently the technicians did not have the adequate training. I was told to use premium grade gas (always used it). 2-3 months ago my SUV gave me vibration at 1500 RPM especially when driving uphill, now gone (not sure if that helps), I decided to use fuel additive and the vibration gone. The dealership found nothing abnormal.
Last night I did a quick relocation of the truck (cold) from one spot on the driveway to another, the temperatures dropped overnight when I started my truck this morning
the check engine light came back instantly. I turned the engine off and on, but the light still on. I have not noticed any difference in how the vehicle drives, nor noises.
I called the dealership and they told me to see if the light will go away in a few days, if not to come back to them, I will post an update on my story.

i've had the po461 check engine light coming on for about 6 months now. its the fuel level sender however the fuel level sender works. the dealer says he will replace the entire fuel pump for $700. ive gotten an o2 senser bank 1 error code & a 'system too lean' error code but they never came back up after they were reset. this car is giving me too many errors.

Update, the next day the check engine light is no longer lit.

Same problem here... Service Engine Soon light comes on and off. Comes on more during the colder months. So far, that light hasn't come on and we've had some really cold nights. I took my 2004.5 Endeavor to the dealership once so they could tell me that nothing was wrong....such a waste of time. I only had 20K miles on the car. When the light does come on, I do feel a drop in power when I step on the gas. But only when I'm getting on the highway.

I also have had issues with my 2004 Endeavor's "Service Engine" light. I am about to take the car in for about the fifth time. I notice nothing wrong with the car--it actually runs well! I have replaced two of the oxygen sensors but now I'm starting to feel like I am getting scammed by the dealerships for repairs I don't need. Any advice?

if you have a check engine light come on with no problems to the car change your oil. its usually because your oil level is low and adding more oil will hit your oil sensor and kick the light back off. it sometimes comes up as a O2 sensor problem code that not a lot of dealerships will tell you, and not a lot of auto parts stores knows about. its a mitsubishi thing.

you people dont seem to realize that there are nearly 150 things that can cause that light to illuminate.
it comes on ANYTIME that ANYTHING causes the emission level of the car to exceed its normal level.
That may or may not effect the way it drives, and it may or may not be damaging.

there are MANY, many software updates for the 04 and 05 endeavors, and all the dealerships are aware of them. Most software updates are also warranted for 8/80.
HOWEVER, there may be an actual problem with any of your cars that is not related to the software, and will need to be properly diagnosed.