My Check Engine light came on and when I ran the codes with my code reader it shows MAP Sensor P000171. Well I have replaced the MAP Sensor, then both the O2 Sensors on the exhaust, the IAC, plugs and wires. Rest the code and after the second time starting it comes on after about 30 miles. Out of ideas.
Check Engine Light on 2002 Volvo S40
by Gerald52 in Smithsburg, MD on April 26, 2011
ANSWER by mastertech6371 , April 26, 2011
171 is not a mass air flow code. a free code pull never identifies a bad part, just a failed system. it sounds like a vacuum leak or a bad pvc. either way you need help from a shop as you have wasted enough money now on this issue. try the directory tab at the top of the page for a shop near you. Roy
ANSWER by Bret Bodas , April 26, 2011
You can find info on how to diagnose this code here>> http://repairpal.com/OBD-II-Code-P0171-and-P0174 I agree with Roy 100%. Your approach has been a waste of money. Such a shame. Take it to a professional and have it looked at. It's probably a split vacuum hose or leaking intake manifold gasket.