could have swore this car gave me a p0171 before, but now its a p0172. Background - i'm off this car in Minnesota, and driving it home started missing real bad, and then wouldn't start at all period. Gave me fuel tank codes, and I discovered that the fuel filler pipe had rusted through. It had only started missing once we hit a heavy rainstorm, so I assumed it had water in the tank and no I swapped in another tank, and it started and ran good. But, after ~20m I got a CEL I think a p0171, but could've been the p0172. I replaced the MAF and no difference. Today, I replaced all the injectors and now get the p0172 immediately. Clear it and it immediately resets. Any suggestions? The coolant temp is normal after warming up. Strange - it was getting bad mileage - mid-30s mpg, but after the new injectors, the mpg gauge is crazy, running 80mpg. If its running rich, I'd think it'd have low mpg, not super high. This car is sold but I need to get rid of this code for the buyer. Any suggestions appreciated.
I got curious about this and did a search; this came up: Diagnosing Automotive Codes P0171 and P0172: Causes and Solutions – Auto Repair Procedures. Doesn't sound like a whole lot of fun, especially if you're on the road. Good luck, and let us know how it turns out.
AI must stand for Alfred, Albert, Alfredo, Alberto, Allen,---hey, wait a minute, a lower-case "L" looks just like a capital "I"---what the---?? Are we talking "A-Ell"or "A-Eye"? And what does this have to do with P0171 or P0172? We've entered SNAFU territory now. And I don't even own a smart phone. Oy!
LOL, major thread hijack. I took the car to a trustworthy shop I know, but not hybrid-centric. He's seeing an ox sensor code that I never got, the upstream sensor. I'm looking in my bootleg, rearranged PDF manual and can't find instructions on how to replace that sensor. Anyone have a vid or service manual instructions? I see a Gen2 video that describes removing the wipers/motor and pan (?), then a heat shield to come at it from above. It says to cut away a another heat shield around the sensor itself to access it with a wrench. Then, remove that shield off the new sensor to put it on. Cutting off the sensor shield doesn't sound right. Also, anyone have a pic of that sensor? Is it identical to the downstream sensor? I saw something that said I could confirm the sensor is bad (causing my p0172) by simply unplugging it. Is that right? The manual only provides Techstream diagnostics using their handheld scanner, checking voltages, etc., which I can't do. Swapping in a new one would be cheaper than paying tech time on that diagnostic procedure. I'm thinking I will do that - drive up to Dallas, replace that sensor, rather than pay my tech guy to do that.
Nope; that would cause the ECU to throw a bunch or other codes, but probably not a P0171 or P0172, because it can't measure that, so I guess yes - you won't see a P0171 or P0172, but a bunch or other codes referring to the upstream sensor disabled. I don't really consider that a solution or valid test. It refers to Al Bundy the shoe salesman on 'Married with Children' or artificial intelligent (you know, garbage-in, garbage-out)
I think the post said that unplugging would make the rough idle go away, if it was the bad sensor misreading temps causing the rough idle. Yeah, it would throw sensor codes. I guess if the idle remains rough, then the sensor isn't my problem? IDK, just hoping there's an easy test before I go to the trouble to buy/swap the sensor.
