P0174 and P0300 codes, rough idle

[chstew05]

I have a 2018 JLU Sahara with a 3.6L. While driving, the auto start/stop unavailable and check engine lights came on with a suddenly rough idle.

I popped several codes P0174, P0300, and P2098. I replaced the upstream bank 2 O2 sensor. P2098 cleared and the idle isn’t as rough. I erased the codes once but they’re still showing even though the check engine light isn’t on any more. I still have the P0174 and P0300 codes (says permanent code). The exhaust has a stronger smell than normal.

While running, the Bank 1 short fuel trim bounced between -4.8 and 0. Lone fuel trim was pretty steady at 4.3. Bank 2 was steady 32.8 for both short and long.

I’m trying to avoid chasing my tail or leaving it at a shop for weeks on end. Is there a quick way to isolate it a vacuum leak, coil/plug/wire or injector issue? I’m pretty mechanically inclined but the V6 is much different than my previous 05 TJ.

Appreciate any advice.

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[gavilan1]

I just went through the same process, same engine, same year. Same codes. 70k miles. Last week. Replaced upstream O2 sensor, bank 2. Problem went away for almost a day. Downstream O2 sensor was bad, as well. Took 10 days to receive part. Engine took several restart and drive cycles to relearn necessary settings. Then gas cap loose lid lit on dash for day and a half. Reset by itself after 50 miles or so of freeway driving. Don’t drive it for more than a day or two with the codes. Too rich fuel mix will kill your cat converters if you run like that 10 days or more (estimated only). A couple of days only, you should be fine. Good luck getting the O2 sensors without a long wait. Happy holidays and trails.

 

[chstew05]

Thanks. I ordered a second sensor. I’ll put it in when it arrives to see if that fixes it. Thankfully I’m on leave for the next two weeks so it’s not causing too many issues for us.

 

[alphawolff]

I have a 2018 JLU Sahara with a 3.6L. While driving, the auto start/stop unavailable and check engine lights came on with a suddenly rough idle.

I popped several codes P0174, P0300, and P2098. I replaced the upstream bank 2 O2 sensor. P2098 cleared and the idle isn’t as rough. I erased the codes once but they’re still showing even though the check engine light isn’t on any more. I still have the P0174 and P0300 codes (says permanent code). The exhaust has a stronger smell than normal.

While running, the Bank 1 short fuel trim bounced between -4.8 and 0. Lone fuel trim was pretty steady at 4.3. Bank 2 was steady 32.8 for both short and long.

I’m trying to avoid chasing my tail or leaving it at a shop for weeks on end. Is there a quick way to isolate it a vacuum leak, coil/plug/wire or injector issue? I’m pretty mechanically inclined but the V6 is much different than my previous 05 TJ.

Appreciate any advice.

You need to reset the fuel trim adaptives in the PCM after replacing the o2, otherwise it'll take many drive cycles to come back into specification.

 

[chstew05]

Appreciate the help. I replaced both sensors, cleared the fuel trim adaptions and it cleared those codes. I drove it for about an hour this morning. When I checked the codes when I got home, I checked the codes and had a P0159 (O2 sensor 2/2 slow response). That’s the sensor I replaced yesterday. I didn’t notice any Issues like I had before while driving it. Is that code normal until the fuel system recalibrates or is there something else I need to check?

 

[alphawolff]

Appreciate the help. I replaced both sensors, cleared the fuel trim adaptions and it cleared those codes. I drove it for about an hour this morning. When I checked the codes when I got home, I checked the codes and had a P0159 (O2 sensor 2/2 slow response). That’s the sensor I replaced yesterday. I didn’t notice any Issues like I had before while driving it. Is that code normal until the fuel system recalibrates or is there something else I need to check?

Double check you replaced the correct sensor with the correct OEM part. 2/2 Is left bank downstream

 

[chstew05]

I replaced it with 68224424AA which is the same number that came out of it. I know the upstream, passenger side is a different one but I think the other 3 are the same. The Mopar website is about as clear as mud on it too.

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