p0171 code replacement parts
 

good day all, I have the damn 0171 code on my 2002 volvo s40

almost 60K miles I did a full tune up since I had a misfire so I changed both coils also and the plugs car ran like a champ today the outside temperature creaped up and as I was slowing moving in traffic the car kept wanting to stall until it did but started right up and I drove for a few more miles but somewhat sluggish thinking it may be the 02 sensor if not a vacuum leak somewhere


1. which is the oem brand replacement for the o2 sensor
2. as I removed the oil fill cap while it running I hear a drone like sound and specs of oil flying out is this normal? (thinking maybe pcv replacement also?
3. if MAF is the culprit, which brand is OEM, volvo is like 200+
4. update I also changed the FPR and thermostat and engine temp by the thermostat all with OEM volvo parts

thanks all

I'd start by checking for vacuum leaks. you may need to get a smoke test but check the tubes under the intake manifold. next is listen/feel for exhaust leaks particularly around the flex pipe.

Oxygen sensors are fairly generic designs and not brand sensitive - Bosch makes the oem but the difference from model to model are in the connector/harness length. (you can even splice in a generic Bosch 4 wire sensor to save a few $$ but I doubt its the O2 sensor.

MAF - you can start by buying some CRC MAF cleaner and wash any oil/residue that may be on the wire grid. Again I believe Bosch is the OEM vendor. Not sure if the gen1s are sensitive to the MAF part number but some of the T5s are...

PCV - the tests for a clogged PCV is to pull the dipstick and check for any smoke and change in noise (ie whistles) then do a rubber (surgeons) glove test. with the dipstick back in, remove the oil fill cap and put the glove over the oil filler and start the engine to idle. If the glove inflates you have positive pressure in the crankcase not venting to the intake. If the glove pulses in out or sucks in slightly, you are good.

Thanks for the reply awesome, I am going to concentrate on checking for the vacuum leaks on the intake side trying to trace and hear the hoses while car is running a little difficult, seems some odd hoses with vacuum tees all over the place, if it is a hose to the pcv valve is it recommended to replace the whole system or just the hose part and pcv oil separator part.

seems like a lot 270+ for a pcv valve kit ???

the PCV kit includes the oil separator (aka flame trap), and a set of hoses and assorted bits. They can easily be found online - check out FCP Euro, eeuroparts, IPD USA to start. For Genuine Volvo, I shop at Tasca parts. Just got some S40 parts today from FCP too :-)

thanks I may get the pcv kit but I tried the glove test with my oil fill hole and it nearly sucked the entire glove inwards most definitely the pcv is operating fine cant clear this P0171 code

ill keep looking for a vacuum leak some where after I clean the maf some then probably change the o2 sensor last

the car only had 58.8K miles

The 2001 model year had an issue where the upper O2 sensor was wired incorrectly from the factory. If this also affected the 2002 models then make sure you have the extra wiring harness on your upper O2 sensor. Basically it connects between the stock O2 sensor and the firewall. We have a heated O2 sensor and the power, ground, and sensor wires from the car were not aligned with the corresponding wires on the O2 sensor connector. The extra harness corrects this problem.