PO171-178 codes?

disco3Andy

Member
Apr 11, 2019
7
0
19
Cleveland, ohio
have an amber CEL and i ran an OBD and it sowed OBD codes PO171 thru 178. The codes were identical. bank one too lean, next code; bank 2 too rich. They alternated like that or all 8 codes. Anyone have an idea what this could mean? I read it could be fuel filter needs changing, air filter could be leaking. Any insight would help, thanks.
 

jprover2

Well-known member
Apr 8, 2017
108
2
Birmingham,Al
It will be something that affects both banks, MAF is one item. You can clean the MAF and clear the codes to see if that helps. There is not going to be a straight answer without having proper equipment to diagnose this. Vacuum leaks can also cause lean or rich codes across both banks.
 

jprover2

Well-known member
Apr 8, 2017
108
2
Birmingham,Al
Throw parts at it, don't worry about diagnosing. And when it's still doing the same thing "or having more problems" we wonder why repair shops charge so much to diagnose a vehicle with several new parts that are not "known good". Just because a part is on the shelf at autozone does not make it "known good". You're not driving grandma's Buick anymore. Electrical parts/ sensors need to be high quality or genuine. AutoZone's deadlast brand is far from quality.
 

tscottg

Well-known member
Mar 21, 2010
189
0
Roanoke, VA
"You're not driving grandma's Buick anymore. Electrical parts/ sensors need to be high quality or genuine. AutoZone's deadlast brand is far from quality. "

Amen to that... I cannot tell you how many LR3 and RRS came into the dealership during my time as an advisor (8 years) with Advance Auto or Autozone MAFS causing problems. The MAFS is likely your issue...Buy a genuine but also check the accordion/flex portion of the intake tube for cracks.