Truck seems to be running fine but is throwing these codes. New to the forum and have been reading a lot. 2004 discovery 2 with 90,000. Cleaned MAF cleared codes and codes came back. What next? Upper o2 sensors? Or replace the MAF?

 

Tey clean maf, let it dry completely. If not replace with original bosch part. Then check codes if o2 code disappears in time.

 

Those lean codes very often indicate vacuum leaks. Check for that before throwing parts at it.

 

Cleaned MAF already. Was looking at hoses for vacuum leaks... found that the secondary air flexible hose is shot! Will this cause those codes? And if it can throw those codes why Does that hose cost over 100 bucks? Is it made of gold???

 

To which hose are you referring? The corrugated metal tube that connects the Sai solenoids to the head? Robber line that feeds the solenoids? Or the vacuum line that actuates the solenoids?

 

It looks like a ribbed plastic line. Really brittle. I just got those codes and this line looks like it has been **** for months.

 

I would guess that it's the vacuum line.

 

Actual name is...secondary air flexible hose

 

no thats prob the pump feed lines. try taping them up with electrical tape. if most of it is still there this should work for the purposes of diagnosis.

however, i dont believe this could cause the lean codes. unless they are the type of code that suggest the opposite of what the problem is. essentially the computer is saying, "ive pulled all the fuel i can but the engine is still running rich". I fought the same "lean" codes but i could never get a definitive answer on whether they were telling me that the engine is in fact running lean despite the computers tuning as rich as possible, or that the engine is running rich, despite the computer tuning as lean as possible.



actually, the P030 code is a sensor malfunction and the 071 confirms this. the P1171 and P1174 are fuel trim out of whack. So its most likely the up stream sensor. Check for bad wires on the front o2's and fix as necessary. install Walker o2's if you cant find any wiring issue.

 

Ok.. electrical taped that line and it looks good. Went under truck to check out the upstream bank 1 o2 sensor and plug has oil all over it. Can't check workability till I get her up on some ramps for easier access. A little tight under there!!! Anyways, looks like oil is coming from valve covers. I'll try and see if I can tackle that project soon. Thanks for the help! This site is a great asset!! If I don't feel comfortable handling the valve cover gasket change about how much does a shop charge for this fix?