SES and P0171 and P0174 codes

[Whoopitupinmo]

OK guys - here it is. Cleaned the MAF reset codes, stayed reset for 10 starts, total of 40 miles. Then while sitting idle at the bank drive thru SES came back on, same codes. Also, my 2001 X5 4.4 has 103K with no other issues. Great car just trying to clear up the SES prior to emmisions test coming up soon.

Any suggestions??

Thanks

[onlinealias]

Vacuum leak somewhere...you are going to have to execute one of all the various methods for determing where the leak is, starting at the front of the manifold and its plastic down to the head ports till you find it. Can be as little as the plastic tube is loose on the intake to the manifold to a vally pan gasket failure. Your mileage is about the time this kind of thing starts happening. One other thing, sometimes cleaning the MAF isn't enough, you have to replace it. Just depends, as the computer doesn't know whether the MAF is sending bad data giving the lean condition, or there actually is a lean condition due to a vacuum leak. Lean due to bad MAF or lean due to vacuum leak looks exactly the same to the computer, and it therefore throws the same code.

One thing you can know for sure, it isn't an 02 or other sensor problem, as the computer has set both banks as lean. This means the problem is on the top of the motor, before anything divides to one bank or the other.

[Whoopitupinmo]

Thanks for the input - I will have him check out based on your reply the beginning of next week. It's beautiful here is Chitown and time to get out and play for the weekend.
I keep you posted.

[Whoopitupinmo]

Checking for vacuum leaks today. Any other options in case that doesn't work? Do you really think a fuel filter will change. Tried fuel injector cleaner twice as well. No change to SES

[onlinealias]

There is nothing else to it. If you replace the MAF and/or find the leaks, the codes will go away. Injector cleaner, fuel filter, magruder valve or whatever have little to do with it.

There is a level of tolerance to leaks the computer will take, I believe that it is 10% one way or the other. Once it get consistantly over 10% compensation for a rich or lean condition, the computer throws a code. Once you bring it back to within tolerance, the code is no longer recorded.

If the fuel side was involved, you would almost certainly be getting other codes in addition to the ones you have.

[Whoopitupinmo]

OK - here's the update. Pulled the engine cover and started checking all the hoses we could find. Found a bad hose in the rear of the engine, we think the crankcase oil air seperator hose with a hole in it. Temporarily fixed that hose and ordered the parts. The SES has gone off and stayed off so far. Thanks for all the input.

[Whoopitupinmo]

Well after 40 miles the SES came back on. Waiting for parts. Hope this works. Now it seems as though the AC is not working too.?? Any help

[Whoopitupinmo]

Hi guys and gals - Well here is what we did so far.
Cleaned MAF - changed out the 2 crankcase oil seperator hoses, new air filter, also changed the spark plugs while in there.

So far the codes are gone.

Great site!!!!

[Whoopitupinmo]

HELP - Just put in the new MAF sensor and the car now seems to accelerate very hesistantly. What could be the problem.