My wifes @002 XJ8 has four fault codes! PO171,PO174, P1642, and P1000. What do these mean? Guy at Advance thinks I need to replace four O2 sensors at about $100 each!

 

P071 and 074 are saying that both banks are running lean. The most common problem is an air leak in the duct between the air filter and the throttle body. Changed the air filter lately? The duct is prone to developing cracks in the accordion section located directly above the exhaust manifold. Also check the full load breather tube and clean the part load breather tube orfice. The P1642 is a communications network failure. Get everything else resolved and it will probably go away. The P1000 is reporting that codes have been set and not resolved by drive cycles.

You do not need new 02 sensors.

 

Wow, Thanks so much for the quick reply! Your answer makes sense because we just got it back from a shop where they replaced the water pump as well as replaced the ABS module/pump assy. with a used one. I'm guessing they tweaked the air inlet assembly during their repairs! Thanks again!

 

You were 100% correct! I just went out and inspected air filter box and found one pleat of the filter caught in the box. After talking more to the wife, turns out after the shop I mentioned before, she took it to a oil quick-change place and said someone there had a very hard time removing and then replacing the air filter. Now my question is, now that I've fixed it will the "engine" icon turn off itself?

 

My experience is that the engine warning light will go away by itself eventually after having these codes, but I don't know how many cycles/hours are required for it to happen. Did the Advance guy read the codes? If so, you might ask him to erase them... that'll make the light turn off right away.

 

Thank You!

 

As for the codes this should help http://www.gusglikas.com/images/Auto...J27%201999.pdf This other attachment might help you track down the vacuum leak causing the P0171 & P0174 codes http://www.gusglikas.com/images/Auto...otos/P0171.pdf I would first check your filter box and see if it is not closed properly causing your leak. Hope this helps! If you elect to clear the codes first jot them down for documentation and the date cleared.

 

Thanks Gus!! Great info!

 

Yes, it will take 3-4 good, complete driving cycles (little bit of everything - high speed, stops, starts...there is a writeup on Fords cycle in the FAQ at the top of this subforum list) before the light will disappear on its own from these codes. It happened to me as well after the same lean bank codes.