What are the probable causes of P2197 & P2098 codes in my 2010 4.6L F150 engine? I initially had a P2098 code with MIL constant on, and it was suggested that I change the downstream O2 sensor on the passenger side. I changed that O2 sensor yesterday, and it instantly turned off the MIL. I thought all was well, so I drove it three times yesterday for short trips (4-5 miles), and on the third trip the MIL came back on. I had the codes read this morning and it is now throwing a P2197 code as well as the P2098. The truck seems to run perfectly fine; although, I think it may be missing very slightly at idle when the truck is in gear and stopped at a stop light or intersection. I appreciate any assistance that can be given me regarding this issue.

 

do you have access to a scan tool with live data capabilities this could be a big help if you do from what i have seen P2197 is a lean condition up stream of the converter not down. if it was down stream is should not affect idle at least being lean for the most part. it would be nice to know long and short term fuel trim and to be able to look at the up and down stream sensors compared to each other once the engine has reached operating temperature. you can test these type oxygen sensors. I see you only dealt with the downstream sensor.

 

Thanks for replying....much appreciated. I unfortunately don't have access to a scan tool with live data. The cheap version that I had purchased at Autozone a few years back only lasted for a season, so I had them read the codes that I posted at the store. Would it be to my advantage to have the codes read by a mechanic with a better reader or is there a reasonably priced scan tool available? Otherwise, are there other tests I can do initially? Also was suggested a possible vacuum leak, MAF sensor, fuel filter? Truck has 40,000 miles on it.

 

you do not need the scan tool i was just curious it can at times make thing easier but for this case i do not think you need it. if you want one that can read live data they are probably about 90 or 100 bucks it been i while since i have looked at the simple code readers so i could be off. the code that seems to be the issue is the upstream sensor code. a fuel filter should affect both banks of the engine the same as it feeds both engine banks these trucks have one filter. does the truck run rough all the time or just once it is hot. The air fuel sensors should not come in to play until the engine is hot as their is no real need on a cold engine. i would try getting the sensor to report rich or lean add something like propane in to the engine or cause a vacuum leak below the throttle plate and see if it throws a code for lean or rich. you could try unplugging the sensor and see how the truck reacts. if those are your only codes then that should be a start.

 

OK. I'll give some of those ideas a shot, hopefully this afternoon. A couple questions, though, so I'm clear. (Sorry...I don't want to waste more time than I already have. Based upon what you're telling me, I don't think I was getting good advice before regarding changing the passenger side downstream O2 sensor.)

1. Is the bank I'm working on the correct side? Should I be unplugging the passenger side, upstream sensor or driver's side?

2. Also, you can see I'm not a mechanic, how would I cause a vacuum leak below the throttle plate?

Also, regarding the idle, I'm honestly not sure that it's worse when hot or cold. It's such a slight 'stumbling' that I'm not sure I would even have noticed it if not for this code being shown.

 

you should be on the driver side bank 2 sensor 1 upstream the converter. remove a vacuum line of any sort that would cause the engine to run rough or create a lean condition. I think your advice on the sensor replacement should have had a diagnosis along with it before the sensor was condemned. you could try removing the power brake booster vacuum connection the truck may or may not stall just find a suitable vacuum line that the engine is able to run without but very poorly. if you have any questions be sure to ask. i also want to make sure you know the sensor you are dealing with is before the converter since you still have a code for the catalyst that can be a separate issue unless you truly have a lean condition inside the engine.

 

Carguy, I have to apologize. I got called away for work and was unable to look into this further, so I am hoping to get a chance this weekend. Before I left town, however, I did realize that I had left the air filter compartment unclipped after having checked to make sure the air filter was clean. I secured it and drove the truck a number of times since. I had the codes read once again yesterday at Autozone, and interestingly, now it is only a P2098 code. The P2197 code is no longer there. Should I still remove a vacuum connection forcing truck to run rough, and if so, I'm assuming you'll need a code that is thrown after that occurs?

 

Since the P2197 code went away and the truck does not run out of the usual then you should not have to do any further testing as for engine performance. The code that is now present is for the emission control system and beings it set a lean code that tells you a few things the input or output and wiring to the sensor could be at fault a new sensor issue installation issue or an issue with what it monitors. Does your truck have any noticeable exhaust leaks if so that is typically when a code would be sent as and air leak would allow lots of air to flow past the sensor their for setting a fault code. normally this type of code is set because of an air leak on the other hand it still could be an issue with the exhaust system and emission control. one other thing that is most common that would cause this code to come back would be the engine computer still has not adjusted to the new sensor. for right now i would suggest keeping the code that went away in the back of your mind focus on the original code or issue you started with but if you can look any were before or at the sensor for an exhaust leak do you now how to look for leaks. and one more thing how did the connection at the sensor look was it corroded at all any burned frayed wires.

 

CEL is still on today after several miles (350-400) and several engine cycles, so I'm thinking that it is more than computer still adjusting to the new sensor. I got underneath and looked at the O2 sensors and connections on the driver's side; all looks good - nothing corroded, burnt, or frayed. I do not know how to check for an exhaust leak. If you could give me some insight on that it would be appreciated.

 

Take something like a dish rag and tuck it in the tail pipe of the exhaust and put a zip tie around if it wont stay on its own. do that without the engine running then you can fire the engine up and listen all around the pipe particularly right before the suspect senor back up to the engine feel all around for out let of exhaust fumes and look for any soot or dirt like what you would sometimes see in the exhaust it self. If this does not yield any thing you could do this same thing but this time use something like sea foam and let the engine take it in through a vacuum link this will create a bit of white smoke and the only place for the most part it should be seen is at the outlet look for were the smoke comes out. If for some strange reason this does not show anything which i think its a good bet that it will theirs is still more ways to diagnose this issue without much effort or time consumption. the white smoke is not at all necessary but i have seen it used i do not like it to much if the engine has no real need for it but it can make it easy to find. based on what you have told me and what i have gathered this is about the best way for you and should be the essayist start to find this issue beings the lean code up front went away and you replaced the sensor that only leaves about a couple things exhaust or emission system malfunction new sensor or what controls it or most of the time a false lean. also their are typically 2 types of leak air leaks in and exhaust leaks out.

 

OK...I know this is an old thread, but i hate it when people don't report back after a problem has been solved. I have had the truck in and out of the dealer three times in the past few months to try to diagnose this - initially to no avail. Finally, this past week they believe they located the problem. The intake gasket was bad and has been replaced. They're certain this will/has solve(d) the problem.

Thanks for all of your help.

Update: Picked up the truck and the check engine light has stayed off. NO issues with idle - problem solved...