07 Prius 250,000 miles. Fuel mileage like 32 MPG. All the time. Someone said converter clogged took care of that did not help. Had an air fuel sensor off a 2nd gen Prius, with a hundred thousand miles. Decided to change out figured it couldn't be any worse than mine with 150,000 last miles on it. Weird thing is car decided to start running terrible even worse gas mileage may be 25 and rough idle. Also decided to throw codes and red triangle go figure. See attached picture with Codes. After resetting codes everything seemed about the same as before back to 32 MPG. Guess I'll just leave the newer one in there. Has anybody ever seen this or have any idea why it would throw codes at first? Most important anybody know how to get better MPG out of it? Thanks appreciate any help I have a great day!!!
Check for VACUUM leaks, if nothing found watch the B1S1 upstream O2 data while spraying some carb cleaner in throttle , should go full rich at .9v if voltage cannot be raised close to 1v then O2 sensor is bad. From the codes your getting I highly suspect it is, indicating lean to computer which is compensating rich causing poor mileage SM-G960U ?
Might try something for the injectors, like kreen, berrymans b-12 chemtool, or anything with PEA (aka techron) in it. Here is the workup for DTC P0171 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Repair%20Manual/04pruisr/05/2054m/cip0171.pdf Here is the workup for DTC P2195 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Repair%20Manual/04pruisr/05/2054m/cip2195.pdf
I did check for vacuum leak seem like throttle body gasket was bad.I think I got that to stop leaking but seems to still be leaking around a butterfly somewhat. Is there any repair for that? CO2 did Reed .99 with carb cleaner in throttle body. Also did drop a bottle of PEA in tank three days ago. ALSO NOT SURE IF I FOLLOW THE TDC workup YET BUT I'LL DO SOME MORE studying. Thanks to all!
Upload picture of techstream maybe it will help with diagnosis. Also took it for a test drive fuel mileage has not gained.
Have you cleared the codes yet? If not can you see if you can find freeze frame data for when the codes set (never used a tech stream so not familiar with where to find it). looking at that screen shot shows no fuel trim issues at that engine speed and that time . That doesn't mean the upstream sensor (actually labeled as AFS air fuel sensor on this model) is failing at some point and seeing the freeze frame data might give a clue. The O2 data listed as B1S2 is the downstream sensor (used mostly for catalyst efficiency testing)which will be in the .1-.9v range . Whereas the upstream AFS (which the codes set relate too) will be around 3.3v with higher than 3.3v being lean and lower that 3.3v being rich (the opposite of the downstream O2) SM-G960U ?
Hey thanks for the information. I'm not real good with techstream either. Wish there was a good educational video to learn a lot more about it. Not sure how to find past freeze frame data. But I will do some more research! At this point it's not throwing any codes not sure if it was just real on happy with getting a different oxygen sensor. And took a while to like it??. Bench testing he heater resistance on the old AF sensor was 2.5 ohms. Which I believe is good. Don't know about the other side of it. But it never threw codes like this newer one, did when I first put it in. Thanks again!
What did the old catalytic converter look like inside, and did you save it? (150k isn't much on a cat) When were the plugs last replaced? Could you describe 'rough idle' a little more, is it missing and shaking?
Sounds like you've cleared the codes so wont have any freeze frame data stored. But worth learning how to retrieve it. Maybe between replacing AFS and fixing vacuum leak at throttle body you fixed it. If it had learned bad fuel trims it will take awhile to relearn so may have run rough for a bit as it relearns correct trims. A bad hybrid battery will cause bad mileage as the motor will run most of the time (basically turns it into a gas powered car pulling a heavy battery around) .I purchase my 04 with a bad battery and the dreaded p080a code replaced the bad cells in the battery and milage was about 50-52mpg for about 9 months then I knew something was going bad as acceleration slowed and engine started running a lot more than usual mileage started dropping to about 45mpg then a week later leaving work accelerated out of parking lot all the warning lights came on with the p080a replace hybrid battery code(milage was down to 40mpg) . Cleared it but knew it was rebuild time again . Monitored voltages and found the bad cell ,replaced the bad cell and now I'm back to 50mpg. So watch your battery status on the MFD and if if going up and down rapidly and dropping into purple a lot causing motor to start this might be causing your terrible mileage. SM-G960U ?
This 07 actually has 250,000 miles on it that was the oxygen sensor donor car with less mileage. Converter was not badly clogged. Did Sounds like missing at idle. Plugs replace roughly 10,000 miles.
Not sure what the total storage capacity of the battery might be. But difference between all the cells never goes more than 0.25 quotes difference. I have been told that means it is a good battery. And if not I wouldn't know what cells to replace? Do you think it'd be a good candidate for the grid charger battery reconditioning? Thanks to all!
You can test the modules under load, while driving and stopping. If none are coding then no pressing need. If the HV battery hasn't failed, it would be a great candidate. A long shot, but clean the MAF if you haven't recently. Try reinstalling the old A/F sensor and see what happens. The kind of engine shaking you describe should be logged in techstream. Can you clarify that the new (used) catalytic converter and upstream A/F sensor are both OEM (denso)? Were the 10k old spark plugs purchased locally or online?