Good analysis on the case here where it is only the one bank! It’s frustrating that everyone suggests the MAF sensor, fuel delivery, fuel filter and such which should impact both banks, not just one. And it seems that too many people are quickly blaming the code on the upstream bank one O2 sensor, which seems like “shooting the messenger” instead of pursuing the actual problem.
I've been battling that exact code for weeks. I checked my pcv valve, cleaned it out and it rattles fine, but I bought another one because they are so inexpensive. No matter what end I blow on or suck on simulating a vacuum, I never get a perfect seal. This is a grand voyager v6 3.3 1997. Just how air tight should they be? The new one is a mopar genuine oem. I was expecting the same result as sucking on a straw with my finger plugging the other end- no air coming through at all.
Having both codes means your engine is lean on both front and rear banks. Chances are you have an air leak somewhere between the air filter and the throttle body. My guess would be that one of the black rubber air intake hoses is cracked...the one closest to the throttle body, as that is AFTER the mass air sensor, so that's where you would get "unmetered air" into both banks. But for the extra $10, I'd say do the PCV valve while you're at it (especially if you haven't already replaced PCV)
Any idea for this. I have a 2014 sienna 140k miles. Replaced MAF 2 times and now P0171 and P0174. Would replacing this part fix both codes? Or you think it’s the O2 sensors?
It's more likely you have an air leak after the MAF sensor. Check the rubber intake tubing between the MAF and throttle body. That's just my guess with the next on the list to trouble shoot.
Van ran fine...no misfires or hesitation. It just had the CEL code. The trouble is that the computer could no longer fix the fuel mixture within the factory parameters, which sets off the code.
Good analysis on the case here where it is only the one bank!
It’s frustrating that everyone suggests the MAF sensor, fuel delivery, fuel filter and such which should impact both banks, not just one.
And it seems that too many people are quickly blaming the code on the upstream bank one O2 sensor, which seems like “shooting the messenger” instead of pursuing the actual problem.
Yep, even when you go to reputable mechanic or the dealer, it can seem like they fire the "parts-cannon" first, then trouble shoot second!
Did you use any thread sealant with the new PCV valve? Is it required?
@@vistablue2984 no thread sealant required on the PCV valve
I've been battling that exact code for weeks. I checked my pcv valve, cleaned it out and it rattles fine, but I bought another one because they are so inexpensive. No matter what end I blow on or suck on simulating a vacuum, I never get a perfect seal. This is a grand voyager v6 3.3 1997. Just how air tight should they be? The new one is a mopar genuine oem. I was expecting the same result as sucking on a straw with my finger plugging the other end- no air coming through at all.
PCV is a one way valve. Air should move toward the vacuum hose and NOT the other way.
I got p0171 and p0174 should i change the pcv valve?
Having both codes means your engine is lean on both front and rear banks. Chances are you have an air leak somewhere between the air filter and the throttle body. My guess would be that one of the black rubber air intake hoses is cracked...the one closest to the throttle body, as that is AFTER the mass air sensor, so that's where you would get "unmetered air" into both banks. But for the extra $10, I'd say do the PCV valve while you're at it (especially if you haven't already replaced PCV)
any updates about your fix? My sienna threw the same codes.
Definitely enjoyed video and found info helpful!
Glad you found it helpful!
Any idea for this. I have a 2014 sienna 140k miles. Replaced MAF 2 times and now P0171 and P0174. Would replacing this part fix both codes? Or you think it’s the O2 sensors?
It's more likely you have an air leak after the MAF sensor. Check the rubber intake tubing between the MAF and throttle body. That's just my guess with the next on the list to trouble shoot.
What were symptoms on the car? Any longer cranks to start the car?
Van ran fine...no misfires or hesitation. It just had the CEL code. The trouble is that the computer could no longer fix the fuel mixture within the factory parameters, which sets off the code.
Going where others don't go...