I only get a MAF code when pulling my racecar (28ft enclosed trailer) for over an hour. I have to go atleast 60-75 miles before the code comes up. I have a stock air box and have checked for leaks and found none. I can drive 1,000's a miles empty and wont get any codes. Any ideas?

Which code is it throwing exactly? Have you cleaned te MAF? They sell a special cleaner at the auto parts store. Have you recorded the PID with EFI to see what it's doing?

Do you have the EGR Valve?

If so, that is tied to the MAF as well, I used to get P0101 all the time, now I am down to a P1404.......Just asking, but look at cleaning the Sensor first.

But let us know if you have the EGR as well.

Do you have the EGR Valve?

If so, that is tied to the MAF as well, I used to get P0101 all the time, now I am down to a P1404.......Just asking, but look at cleaning the Sensor first.

But let us know if you have the EGR as well.
Not to hi-jack the thread but, what about the EGR? And, how do I know if I have one?

I have an '01 so I'm thinkin' I don't.

The EGR and the MAF are tied together somehow, and the only way to know if you have one is look. On the Passenger side of the intake, there will be a tube with coolant lines running to it, and the EGR valve at the eng of the cooler. Or you can check your build sheet and look for the build code.

California models, and Fleet Vehicles got the Emissions crap, so yes LB7's did come with the stuff. My truck came from Texas, I do not know about other locations, but I know my truck has it.

Do a search, there have been pictures posted many times of what it looks like installed.

The EGR and the MAF are tied together somehow, and the only way to know if you have one is look. On the Passenger side of the intake, there will be a tube with coolant lines running to it, and the EGR valve at the eng of the cooler. Or you can check your build sheet and look for the build code.

California models, and Fleet Vehicles got the Emissions crap, so yes LB7's did come with the stuff. My truck came from Texas, I do not know about other locations, but I know my truck has it.

Do a search, there have been pictures posted many times of what it looks like installed.
Many thanks!! Will check it out.

Do you have the EGR Valve?

If so, that is tied to the MAF as well, I used to get P0101 all the time, now I am down to a P1404.......Just asking, but look at cleaning the Sensor first.

But let us know if you have the EGR as well.

Hey John, EFI live will cure that...did you know?

Hello I was wondering if I could ask a question here about the MAF P0101 Code. My 2002 2500hd has a K&N cold air intake and I cleaned the filter the other day and then the next day the check engine light came on. Using the My Edge Computer is showed the P0101 code. I cleaned the MAF with CRC MAF cleaner and reinstalled it. Cleared the code and about 40 miles it came back on.

Do you have any ideas how to correct the issue? Should I recleand the air filter and use more oil?

Any help will be great.

Hello I was wondering if I could ask a question here about the MAF P0101 Code. My 2002 2500hd has a K&N cold air intake and I cleaned the filter the other day and then the next day the check engine light came on. Using the My Edge Computer is showed the P0101 code. I cleaned the MAF with CRC MAF cleaner and reinstalled it. Cleared the code and about 40 miles it came back on.

Do you have any ideas how to correct the issue? Should I recleand the air filter and use more oil?

Any help will be great.
You might have over oiled it. I used to get that code after I cleaned and oiled and realized I was over oiling. Also Tolli is right about the EGR, I got it p0101 a lot until I traced the problem down to a faulty sensor/valve. No codes in a long time(knock on wood).

Thanks Tileman,

I'm a NOOB with Diesel trucks. Would a 2002 have an EGR valve? I do live in California.

I think I will take the filter off and reclean the filter and not put so much oil. Do you have a K&N Air Cleaner?

Hey John, EFI live will cure that...did you know?
I have EFI LIve, how is this accomplished?

Hello I was wondering if I could ask a question here about the MAF P0101 Code. My 2002 2500hd has a K&N cold air intake and I cleaned the filter the other day and then the next day the check engine light came on. Using the My Edge Computer is showed the P0101 code. I cleaned the MAF with CRC MAF cleaner and reinstalled it. Cleared the code and about 40 miles it came back on.

Do you have any ideas how to correct the issue? Should I recleand the air filter and use more oil?

Any help will be great.

you might have damaged the MAF when you took it out to clean it. they are incredibly sensitive. you can't tough the wires at all on them, you can't drop them, make sure you don't handle them rough at all. anyone ever tried unplugging theirs while running? if so what happened? with fords to test them your supposed to unplug them and if the idle changes or the check engine light comes on then it's working. i unplugged mine yesterday to see if it was working and it made no change. we weren't sure if the MAF sensor is working at all on my truck.

you might have damaged the MAF when you took it out to clean it. they are incredibly sensitive. you can't tough the wires at all on them, you can't drop them, make sure you don't handle them rough at all. anyone ever tried unplugging theirs while running? if so what happened? with fords to test them your supposed to unplug them and if the idle changes or the check engine light comes on then it's working. i unplugged mine yesterday to see if it was working and it made no change. we weren't sure if the MAF sensor is working at all on my truck.
It could be the EGR system then, if you have one...

Hey John, EFI live will cure that...did you know?
I have heard that from some Dutch guy that lives in Idahoe:p:

Also the truck will run if the MAF is disconnected, just not very well.

i have no egr at all. it is a federal emissions truck. my truck runs perfect with the MAF disconnected. this is why i think maybe the engine is running in open loop and not reading off the MAF sensor. just wondering if maybe my MAF went for a poop.

I have EFI LIve, how is this accomplished?

For the LB7 with EGR it is Engine Calibration>EGR>Parameters.
B1501 is changed to 300 (engine goes above this value, RPM, the EGR will not come on).
B1504 is changed to -39 (If engine temp is above this value, the EGR does not come on.
B1505 is changed to 151 (If engine temp is below this value, the EGR does not come on).

Effectively there is no operating scenario that will allow EGR operation with these values. After these settings, well hey, my vacuum pump kinda rather disappeared. Don't know how that could've happened. :D

I have heard that from some Dutch guy that lives in Idahoe:p:

Also the truck will run if the MAF is disconnected, just not very well.

I'm telling ya John to go north young man, go north.

DTC p0101 "DISABLE" < Fixed it for you ;)

Hmm may need order a MAF sensor I re-cleaned the filter and took the MAF off and re-cleaned it but with no luck. The light came on unless the MAF is bad.

Does anyone else us a K&N cold air intake? I notice that the MAF doesn't seal tight in the tube and I had to use silicon to seal a little better.

I am out of town (not in truck) so I can't check the code. Its just really weird how it only comes up after towing for 100+ miles. I since bought a bigger race car trailer (40ft enclosed) and pulled it about 50 miles with no maf code.

Do either one of you guys have EGR?

i know i dont and i don't and i think the original poster said he didnt either.

If you have a egr this is what I replaced and haven't seen a code since... check out post # 36 http://www.dieselplace.com/forum/showthread.php?t=324134&page=4
(knock on wood)

i dont have any codes. there is just no change when the MAF is unplugged, and it is overfueling. i believe its injectors but im just trying to rule everything out.