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-   -   Newbie with error code question...!!! Please Help...!!! (http://www.jeepgarage.org/f5/newbie-with-error-code-question-please-help-29707.html)

my1997cobra 10-14-2011 12:55 PM

Newbie with error code question...!!! Please Help...!!!
 
2005 Jeep Grand Cherokee Laredo (3.7 Liter V6)

After filling my tank with suspect gasoline from a company called GoMart here in SW VA :mad: (only because I had no choice but to stop there; only one in the area), I drove approximately 80 miles to a friend's house, and vehicle was turned off for about 5 hours. I started the vehicle back up and began to drive. I drove approximately 50 miles and the CEL came on and I could immediately feel a difference in HP and per the digital fuel economy average on the dash I had lost about 4 MPG by the time I arrived back home. I now have some very noticeable carbon deposits out of my exhaust pipe when pulling in and out of my garage on the floor. Also, the vehicle idles lower than before the light appeared. The next day I took it to a friend's garage the next day and put it on an OBD-II scanner and it populated the following codes:

P0031 - o2 Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
P0171 - System too Lean (Bank 1)
P0172 - System too Rich (Bank 1)

I purchased a Brand New NTK (NOT BOSCH) o2 Sensor from local auto parts store and installed it. I had him reset the codes to see if they would come back and SURE ENOUGH, as soon as I started the vehicle back up and put it in gear to pull out of the driveway it came back on and is still on. I took it to a local dealership the next day and the Service Manager mentioned something about the possibility of it being the PCM. Could this be the ultimate problem or does anyone have any other suggestions? Thanks in advance for any suggestions or advice...!!! :D

robpp 10-14-2011 01:09 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
what kind of mileage is on this rig?

egr comes to mind.

also any kind of exhaust leak might throw those codes too/

my1997cobra 10-14-2011 01:20 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
Has 75,xxx on it right now...

robpp 10-14-2011 02:12 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
egr done at 60K.

my1997cobra 10-14-2011 03:01 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
Wouldn't the EGR have its own error code...?

my1997cobra 10-14-2011 03:12 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
Read somewhere else that the '05 3.7 V6's didn't have EGRs on them...?

Crestwood1001 10-14-2011 03:40 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
Rob knows what hes talking about....

my1997cobra 10-14-2011 04:13 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
Not saying that he doesn't because I sure as hell don't in this case (this is why I used the question marks). I was just reading up on the specs for the 3.7 on WKs in '05 and it said that they weren't introduced until '06...this was from a Jeep Manufacturer site. Also, I'm sure if he does indeed know what he's talking about that he doesn't have to have someone else to reassure him of that... I definitely took into consideration the advise that he gave and appreciate it GREATLY...thanks for your 2 cents though...

my1997cobra 10-14-2011 04:31 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
http://jeepgarage.org/showthread.php?t=27448

Apparently the article wasn't wrong after all... thanks anyway though Rob...

jeepgcoman 10-16-2011 08:21 PM

Re: Newbie with error code question...!!! Please Help...!!!
 
Sounds like a typical dealer response. Why not check the most logical stuff first, instead of just replacing parts until they stumble onto the resolution? All this at your expense too, unless you have a good warranty.

Sounds like the problem started after you put some different fuel in it, right? Do you know what it was? Could it have been E85 or a leaded fuel? Does it smell like regular gasoline? Is the same gas still in the vehicle? If so, the whole system is probably contaminated, including the new sensors. Doesn't take too much, especially if the system is already contaminated. There should be NO carbon deposits anywhere if you've been running a good quality fuel. If the bad fuel is still in it (especially if it's a large amount), I would probably get it all out of there somehow, either by running it, removing the tank or pumping it out, then put some known good fuel in and run it for 50 miles or so. Then replace (or take back as defective) all 4 sensors. Just for giggles you may want to pull a couple spark plugs to see what they look like too. If you're getting lots of carbon, they may need to be replaced too. I don't want to say it, but it would also be possible that the cats. could be bad too. That runs into some $$$. The good news is that if they're bad, you should also get cat. related DTC's.

Bottom line, first try to find out what that fuel is/was, get any remaining out of there, run it awhile with some known good fuel to purge the system, start checking components, and go from there. Good luck and please keep us posted on your findings.

2005JGC 10-19-2011 02:43 AM

Re: Newbie with error code question...!!! Please Help...!!!
 
I need to go to bed so my response will be short,

circuit low is a short to ground indication (typically). if it is open then it will see "high" voltage, if it is shorted to voltage it will obviously see "high" voltage. if it is shorted to ground it will pull the voltage low. This could be from somewhere in the circuit and it could be from an internally shorted o2 heater.

I would first start with your heater code, then move on to your lean/rich as your O2 is the decider of lean and rich. If you have a digital volt ohm meter (dvom) you can compair ohm and voltage readings from your 1/1 and 2/1 sensors (both upstream). if you find drastic continuity differences between the 2 across your heater circuit I would replace the O2 again and pick it up at the dealer. You would not be the first to replace replaced o2 sensors on the forum and you wont be the last.... although some have replaced ALL of them with aftermarket sensors with no fix only to actually fix the problem with mopar sensors.

I am not saying your O2 sensor is the problem, but again start with that issue and move on from there.

my1997cobra 10-20-2011 06:43 AM

Re: Newbie with error code question...!!! Please Help...!!!
 
Thanks jeepgcoman and Andrew for the advice...the Jeep is going to the dealership today and I have printed out your responses to take for reference to their troubleshooting processes also. Will post update tomorrow as to how the visit went...thanks AGAIN...!!! Both of you have a great weekend ! :D


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