P101 Error Code (Mass Air Flow)

Broker

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Oct 17, 2006
Location
Guelph, Ontario
TDI
Black, 2006 Jetta TDI DSG.
I have a P101 error code (Mass Air Flow) on my 2006 Jetta TDI DSG.

Symptoms: Lack of power upon acceleration and lots of black smoke.

I have changed the MAF and still have the same problem. The car is running rough.

I regularly change my oil, fuel and air filters and have used a couple products to remove carbon build up. I do a lot of driving both highway and city and shouldn't have carbon build up problems but it seems I do and have had the turbo cleaned, put in a new "cooler for exhaust recuperation" as the old one had a pivot arm that was seized and had carbon build up around it. Is the EGR next to be replaced?

I have to say that I had my car tuned with Technine about 3 months after buying the car new but that was over three years ago. Could my car be running too rich and it has taken almost three years to accumulate carbon build up or something?

I was wondering if the car needs to be reprogrammed to either the factory settings or have a new performance program installed that could potentially solve this car problem.

Any help would be appreciated!

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Mach1

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05.5 Jetta 5 spd, 06 Jetta DE DSG, 04 F250 6L, 2000 F250 7.3L
Boost leak, check your IC connections..
 

Broker

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Black, 2006 Jetta TDI DSG.
To anyone that can help. JasonP was able to help with the following screen shots:







Any ideas?????
 

DanG144

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Chapin, South Carolina, USA
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2005 A4 Jetta 5spd
I would inspect the cam on any BRM that came in the door running rough, unless there was some other obvious explanation.

What you describe could be caused by a stuck open EGR valve.

One word of warning. When the ECU determines the MAF is not working, it substitutes a value in for the MAF. On the old ALH the stock substitution value was 550 across the board. I have seen some tunes where it was 1250. This value shows up in VCDS as if it was from the sensor.

I thought it odd that both screen shots showed exactly the same MAF value (Edit, now I see they are indeed different, so this is not what is happening.). Could it be that your tuner has a substitute value of 390? It seems awfully low, and would create very low power and no smoke, as long as the EGR stayed closed.

On older PD's it is not unusual to see 100% EGR duty cycle for long periods. It is on the BRM, according to my limited experience.
 
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Broker

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Black, 2006 Jetta TDI DSG.
I am thinking it is a cam issue as well. I brought it in to a specialist and he will inspect the cam and valves as well as doing a possible reprogram, (I had a performance upgrade from TechNine when I bought the car new). There might be a problem with the air/fuel mixture that has caused the problem in the first place. I hope:confused:
 
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JASONP

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Feb 24, 2008
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Guelph
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2015 Golf TDI Comfortline 6spd
Rod Bearing said:
unplug the maf and drive it again.
He's on his 4th or 5th MAF already, trying to help him figure out why?

New filters, TB job in Nov 09, EGR gas cooler in Oct 09,:confused:
 

JASONP

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Broker said:
I am thinking it is a cam issue as well. I brought it in to a specialist and he will inspect the cam and valves as well as doing a possible reprogram, (I had a performance upgrade from TechNine when I bought the car new). There might be a problem with the air/fuel mixture that has caused the problem in the first place. I hope:confused:
If it were an issue with fueling, it would ahve showed up imediately, not 4 yrs later one would think.
We can run some logs next week if you want and cable supports doing so.
 

JASONP

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DanG144 said:
There have also been issues with the Catalytic Converter plugging in these cars, causing excessive exhaust gas recirculation, black smoke, low power.
Aahhhaa, good point which would possibly lead back to a fuleing issue, Ben did mention he does quite a bit of idling in traffic, maybe another venu to explore.
The EGR readings boggle me though, 100.6% ??? sustained at idle
 

Broker

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TDI
Black, 2006 Jetta TDI DSG.
DanG144 said:
There have also been issues with the Catalytic Converter plugging in these cars, causing excessive exhaust gas recirculation, black smoke, low power.
Thanks!

How can this be tested?
 

DanG144

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Chapin, South Carolina, USA
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2005 A4 Jetta 5spd
We stay low tech, but I am always willing to learn a better method.

This is all going from memory...

I do the basic settings block 3 test with VCDS. Normally when the EGR is open you get half the flow with the EGR closed. Say 450 and 225 mg/stroke. If the flow dies off to 120 or so when the egr is throttled open, that is a sign of either an EGR problem or plugged exhaust, causing high backpressure, causing low fresh air intake flow.

You can also do the OUTPUT TESTS, one of them checks EGR function as well, but at idle instead of at 1400 rpm as the BASIC SETTINGS test does.

I also take a log of full throttle operation from 2k to 4k in 3rd, and see if air flow dies off excessively at higher rpm. This can be a problem to judge unless you have a log of the same car/tune during the same run. So then...

Just remove the three bolts from the turbo to the downpipe, tie it back, and go for a short full power run just like before. Compare this to logs from before, and see if air flow is up for a given intake pressure and RPM.
 

Mach1

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Sep 27, 2005
Location
Spicewood, Tx.
TDI
05.5 Jetta 5 spd, 06 Jetta DE DSG, 04 F250 6L, 2000 F250 7.3L
BRM DP is v-band flange, I believe a 6mm allen..

Dan is thinking BEW 3 bolt..

Good thought to check for restriction in the back end, could be Cat clogged..Could be N75 vlave, could be vane activator.

You sure you checked ALL IC piping?
 

JASONP

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Location
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2015 Golf TDI Comfortline 6spd
DanG144 said:
We stay low tech, but I am always willing to learn a better method.

This is all going from memory...

I do the basic settings block 3 test with VCDS. Normally when the EGR is open you get half the flow with the EGR closed. Say 450 and 225 mg/stroke. If the flow dies off to 120 or so when the egr is throttled open, that is a sign of either an EGR problem or plugged exhaust, causing high backpressure, causing low fresh air intake flow.

You can also do the OUTPUT TESTS, one of them checks EGR function as well, but at idle instead of at 1400 rpm as the BASIC SETTINGS test does.

I also take a log of full throttle operation from 2k to 4k in 3rd, and see if air flow dies off excessively at higher rpm. This can be a problem to judge unless you have a log of the same car/tune during the same run. So then...

Just remove the three bolts from the turbo to the downpipe, tie it back, and go for a short full power run just like before. Compare this to logs from before, and see if air flow is up for a given intake pressure and RPM.

Dan I do think you are spot on here car idles bad, owner says he gets crap milage,the EGR Duty Cycle looks (to me ) way too high for idle, the number of MAFs he's replaced in the past few months, and he says he gets tons of balck smoke.

Ben the easiest way I can think of is takke the car to a muffler shop and have them remove the CAT for inspection, OR you can go to a Commercial Diesel Inspection shop and have them do an exhaust analasys.

We can also try turning down the IQ with VAG.
 
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dropdeadsheds

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Jun 5, 2009
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plattsburgh ny
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05.5
Pull egr out and check to see if the valve in the egr is open. Like a car valve it should be seated closed. If you can see light though the seat of the egr vavle thats it. Thats the causes of the black smoke. 3 bolts to pull and wiggle it out on a brm motor. Please check first. I just did one on my 2005.5 jetta brm. David
 
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