[bimmerup-sonny]

This past Monday at lunch, I experienced the "limp" reduced power mode that I've heard about.

It was couple minutes after start and going up on freeway ramp with 5 people in the car,
so I needed to boost engine, but I've done this trip many many times.

Light came on with "Malfunction - reduced power" message, and it only allows me
to drive under 50mph. So I got off the freeway and restart the engine, the error went away, I took the side streets for the rest of that day. Torque OBD scan said:

P0402 OBD-II Trouble Code: Exhaust Gas Recirculation Flow Excessive Detected

Some facts on my car: CBU clean at 71K miles, cleaned 5 and replaced 1
injector at 77K miles, getting MAF error once in a while, been using PS Diesel Kleen
and also Liqui Moly Diesel Purge every 2-3 fill ups

Yesterday and today, I decided to drive the car, and no "limp" issue, I drove on freeway at 65 - 70mph too. Although, I've been taking easy on the throttle. Torque scan said no code reported.

So, I am not sure what to make of this.

Can someone shed some light on this issue? Is this something permanent?
Would it be some kind of vacuum leak?

Sonny

[Yozh]

Probably is your MAF.

[EvanTheBruce]

I had the same issue with my car. Went into limp mode, restarted and it went away. Then a couple days later it went back into limp mode and stayed on. I replaced my MAF with a new OEM unit and my problem was solved. No programming needed.

[Miko226]

Originally Posted by Yozh

Probably is your MAF.

+1

Had to change mine out not far off 70k

[bimmerup-sonny]

Originally Posted by EvanTheBruce

I had the same issue with my car. Went into limp mode, restarted and it went away. Then a couple days later it went back into limp mode and stayed on. I replaced my MAF with a new OEM unit and my problem was solved. No programming needed.

I took it to my indie and he said just wait until a code shows up. Did you see a code at the time?

What kind of cost would I expect to pay to indie garage for this MAF repalcement?

[Yozh]

Just do it yourself, it's easy.

[335dsleeper]

Originally Posted by Yozh

Just do it yourself, it's easy.

1+

[bimmerup-sonny]

Originally Posted by Yozh

Just do it yourself, it's easy.

I would love to do it myself, if somebody can give me some pointers

All I know MAF is the unit attach to the airfilter duct before he engine
intake, not sure exactly what part it is either. I will start researching,
but if I can get some head start from the group, it would be great.

[bimmerup-sonny]

Originally Posted by bimmerup-sonny

I would love to do it myself, if somebody can give me some pointers

All I know MAF is the unit attach to the airfilter duct before he engine
intake, not sure exactly what part it is either. I will start researching,
but if I can get some head start from the group, it would be great.

I found it here, much cheaper than other site... from the image, I think I know exactly what it is now

http://www.partsgeek.com/gbproducts/...ad=47433964212

[Mark M]

Not affiliated in any way, just a plug. Fcp euro is phenomenal to work with and they offer lifetime parts warranty.

I've began to use them now as my one stop shop and can attest the parts warranty is great and painless for exchange.

[EvanTheBruce]

Originally Posted by bimmerup-sonny

I took it to my indie and he said just wait until a code shows up. Did you see a code at the time?

What kind of cost would I expect to pay to indie garage for this MAF repalcement?

I don't remember the exact code but the codes that showed up were not for the MAF itself, they were all reference to the IAT sensor. I replaced the IAT first, cleared the codes and still had limp mode issues. Read the codes again and it still said IAT, so I pulled up a wiring schematic and traced the wires, the MAF and IAT are in the same circuit so I replaced the MAF and my problem went away.

It's very easy to replaced, there are 3x 10mm bolts that hold down the air filter box. Remove that, then there are 2 torx screws that hold the MAF in place. It's a 10-15 minute job start to finish. Sorry, I do not remember the size of the torx bits off the top of my head.

[bimmerup-sonny]

Originally Posted by EvanTheBruce

I don't remember the exact code but the codes that showed up were not for the MAF itself, they were all reference to the IAT sensor. I replaced the IAT first, cleared the codes and still had limp mode issues. Read the codes again and it still said IAT, so I pulled up a wiring schematic and traced the wires, the MAF and IAT are in the same circuit so I replaced the MAF and my problem went away.

It's very easy to replaced, there are 3x 10mm bolts that hold down the air filter box. Remove that, then there are 2 torx screws that hold the MAF in place. It's a 10-15 minute job start to finish. Sorry, I do not remember the size of the torx bits off the top of my head.

The limp mode has not returned.

So, I decided to just clean it for now. I bought some MAF cleaner on Saturday, and took the MAF sensor out to clean it, it was really easy. It does not look too dirty, I did notice the difference, will drive a couple days and see how it performs with a clean MAF sensor.

[bimmerup-sonny]

Originally Posted by bimmerup-sonny

The limp mode has not returned.

So, I decided to just clean it for now. I bought some MAF cleaner on Saturday, and took the MAF sensor out to clean it, it was really easy. It does not look too dirty, I did notice the difference, will drive a couple days and see how it performs with a clean MAF sensor.

After driving with the clean MAF sensor for 2 days, I can truly say it definitely improves. I can feel the low-end torque is back, accelerate and pull smoother.
I would recommend EVERYBODY to clean their MAF sensor, it is so easy to do.

Just pop out the 3 metal clips for the top air filter box, loosen the clamp screw, and take out the filter top and MAF box unit. Take out 2 more screws to remove the MAF unit and spray it with CRC MAF sensor cleaner, let it dry out for 10 minutes, put it all back and enjoy the power again...

[bimmerup-sonny]

Updates:

Limp mode came back, so I decided to replace the MAF sensor 3 weeks ago..
After 3 days running with the new MAF sensor, code P0101 came back, although no limp mode, but then I have not been boosting it. I cleared it and it keeps coming back within a few days of clearing.

I also notice lately, I can feel engine noise in the steering wheel, and the engine seems to idle much louder. Anyone has experienced this?

Am I due for another CBU clean? I cleaned it at 72K miles, and now it is at 95K

[BB_cuda]

23,000 miles seems way too quick. I recall guys talking resetting adaptations when changing the MAF though.

[dmanb2b]

check for loose or split piping/clamps

[bimmerup-sonny]

Originally Posted by BB_cuda

23,000 miles seems way too quick. I recall guys talking resetting adaptations when changing the MAF though.

If I recall correctly, are you referring to the method of
stepping on the pedal all the way for 30 seconds with
the engine off and just the key turned on. I will try tonight.

[BB_cuda]

Originally Posted by bimmerup-sonny

If I recall correctly, are you referring to the method of
stepping on the pedal all the way for 30 seconds with
the engine off and just the key turned on. I will try tonight.

I've never changed MAF before. The foot pedal thing is throttle adaptation. I'm unsure if this does anything in regard to MAF. MAF savvy people will hopefully answer this for you.

[Yozh]

MAF Adaptations are reset via ISTA. You also need to do mean quantity adaptations reset if you change MAF.

[bimmerup-sonny]

Originally Posted by Yozh

MAF Adaptations are reset via ISTA. You also need to do mean quantity adaptations reset if you change MAF.

If you can be a little more descriptive, can these SW be easily bought?

I will do some research, I just did not know anything needs to be
done for a simple MAF replacement

[JuiceQuadre]

Hi, just a quick question, do i need to reset adaptations if i just decide to clean the maf? Sounds like a good easy diy maintanance but i dont want to mess with expensive software right now..

Btw what does throttle adaptation do exactly? Never heard of it.. Can i read somewhere about what different adaptations actually exist in our cars? The throttle adapt isnt the same thing as the auto transmission adapt is it?

Thank you

[bimmerup-sonny]

Originally Posted by JuiceQuadre

Hi, just a quick question, do i need to reset adaptations if i just decide to clean the maf? Sounds like a good easy diy maintanance but i dont want to mess with expensive software right now..

Btw what does throttle adaptation do exactly? Never heard of it.. Can i read somewhere about what different adaptations actually exist in our cars? The throttle adapt isnt the same thing as the auto transmission adapt is it?

Thank you

Throttle Adaptation Reset:

1. Never touch the break pedal & key remains inserted the entire time
2. Insert key and push START Button
3. Press and HOLD accelerator pedal for 30 seconds (some say 5, some say 25 seconds - I did 30 to be sure).
4. WITHOUT RELEASING THE ACCELERATOR PEDAL, push the START Button
5. Release accelerator pedal
6. Wait full 2 minutes
7. Start car normally