PO171 and PO174 codes
PO171 and PO174 codes I got a SES light over the weekend. Pulled the codes and PO171 and PO174 which are bank 1 and 2 lean condition. Also my car is detonating on the top end at WOT. My guess is the MAF is bad. If I clear the codes and go out and go WOT then it comes on immediately. If I clear the codes and don't go WOT at all it does eventually come on but takes it 30 minutes or more. Since at WOT the MAF is the primary sensor that affects the fuel trims I think this is the culpurit. Anybody else have any thoughts? Thanks.
I have the same problem !! I have a aftermarket MAF and have cleaned the area with brake cleaner and it went off for a while but then comes back on. I have been told it could be a vacum leak, to fuel pump, injectors,etc. If you find out what the problem is tell me. Sorry I wasnt much help.
I got lean codes on my other sensors, P0157 and P0137, and it was due to a dirty MAF and a clogged fuel filter. (The MAF being the primary culprit.)
Cleaning it is an easy and cheap thing to do/try. When you do it, be sure to use special-purpose MAF cleaner or non-residue electrical contact cleaner. Brake Cleaner can leave a residue on the elements, fouling them, and will also dissolve the plastic parts on the MAF.
Cleaning it is an easy and cheap thing to do/try. When you do it, be sure to use special-purpose MAF cleaner or non-residue electrical contact cleaner. Brake Cleaner can leave a residue on the elements, fouling them, and will also dissolve the plastic parts on the MAF.
I have already tried cleaning mine with MAF cleaner and it did no good. I was getting a different code about 4 months ago though and I cleaned the MAF then and it went away and hasn't been back so I think that was the MAF on its last leg and now its shot.
A vacuum leak is always a very strong possibility. Check for one by spraying carb/choke cleaner on and around all vacuum lines (PCV line, brake booster line etc) and listen for a change in the idle.
Just to put a close to this thread and give info for future people that do searches my codes ended up being caused by a vacuum leak like many people said. On the passenger side of the intake there is a little rubber hose that goes between the intake and the PCV valve. On the underside of that rubber piece a hole opened up and it was sucking air causing the lean condition. I finally heard it sucking one day when the car was idling and noticed where it was coming from and then fixed it. Codes went away and haven't been back since. Thanks for the help everyone.
