Hesitation/ low power 2005 PD

I have a customer with a 2005 (A4) Jetta Wagon 5sp 150k miles. It is throwing a P0101 code Mass Air Flow Sensor (G70): Implausible Signal.

This all started during a recent cold snap while he was up in Va.
It starts and runs fine until accelerating under load below about 2800 rpm. That's when it runs rough/hesitates(3rd-5th gear). After 2800 it smooths out, but still seems sluggish. Smokes more than normal during this also.


MAF was changed by dealer
replaced fuel filter
checked intake/cleaned EGR
new lift pump
turbo has about 20k on it

Any suggestions?
Thanks!
Todd

Look for the vacuum lines. That's a lot of stuff for a dealer to screw up.

jasonTDI said:

Look for the vacuum lines. That's a lot of stuff for a dealer to screw up.

Click to expand...

Dealer only did the MAF. I've gone over the vacuum lines. It has more power than when you have a vacuum leak.

huuuhhh...? weird.....Did you take a look at the turbo vanes?

Not yet. Boost is going to around 2100 mbar.

its the egr, needs to be replaced its stuck open very minimal that will throw the maf reading off and set the fault.remove the egr it should be completely shut if its open even a tiny crack its no good.try doing a egr basic setting with the vag com.But you will most likly need an egr valve.

The EGR system is something I've suspected. What should the duty cycle of the EGR be at WOT? It currently goes to 100%. Then decreases once you let off the pedal.

Pitboy said:

The EGR system is something I've suspected. What should the duty cycle of the EGR be at WOT? It currently goes to 100%. Then decreases once you let off the pedal.

Click to expand...

Pulled the EGR out again, it closes off completely. Anti shudder valve is not stuck either.

Any suggestions as to what would cause the EGR duty cycle to jump to 100% at WOT?

Pitboy said:

Pulled the EGR out again, it closes off completely. Anti shudder valve is not stuck either.

Any suggestions as to what would cause the EGR duty cycle to jump to 100% at WOT?

Click to expand...

Does it have the correct MAF on it? Parts depatments have been known to hand out the wrong ones and people take for granted they gave them the correct one.

Yup, verified it already.

There is a TSB on this issue...

You have a pm

After reading through this thread, I think I have a similar issue with my 2005 Golf PD. I got the implausible MAF code a few weeks ago and it's smoking on acceleration with a hestitation/jerk at around 2800rpm when giving moderate throttle. I've checked the airflow, boost, etc.. with VAG-COM but I'm fairly new to this whole scene and as far as I can see the values look reasonable. I will watch the EGR duty cycle next time to see if it's going to 100% similar to Pitboy's story. What should normal EGR duty-cycle traces look like?

Cheers!

73kever said:

After reading through this thread, I think I have a similar issue with my 2005 Golf PD. I got the implausible MAF code a few weeks ago and it's smoking on acceleration with a hestitation/jerk at around 2800rpm when giving moderate throttle. I've checked the airflow, boost, etc.. with VAG-COM but I'm fairly new to this whole scene and as far as I can see the values look reasonable. I will watch the EGR duty cycle next time to see if it's going to 100% similar to Pitboy's story. What should normal EGR duty-cycle traces look like? Jharrison, can you fill me in on the TSB?

Cheers!

Click to expand...

Please do not ask me for the TSB! I will help in any way that I can, but I cannot distribute copy righted material. I need access to ELSA and the other VWOA sights to do my job. If I were to distribute said material VWOA would revoke my access to these sights.

I would love to be able to hand out all of the TSB's that no one knows about, but I cannot. VW takes the access they they give rather seriously and the last thing I want is to piss them off. They may tell me I do not get to go to the Virgin Islands....Then my my wife would KILL me!

jharrison said:

Please do not ask me for the TSB! I will help in any way that I can, but I cannot distribute copy righted material. I need access to ELSA and the other VWOA sights to do my job. If I were to distribute said material VWOA would revoke my access to these sights.

I would love to be able to hand out all of the TSB's that no one knows about, but I cannot. VW takes the access they they give rather seriously and the last thing I want is to piss them off. They may tell me I do not get to go to the Virgin Islands....Then my my wife would KILL me!

Click to expand...

I'd like to thank Jeff for providing the TSB #. With that info and the p0101 code, I got back on Ebahn and found it. There's a wealth of information available to you on Ebahn with your subscription. I was unaware there was so much there.

Technical Bulletin 01 07 46 May 7, 2007 2010352

My deceleration value from measuring block group 93, block 2 is higher than the upper threshold value of 1.05, with an average value of 1.19.
So far, the cam timing, breather hose, IAT(G72), MAF are good. Charge air pressure (G31) is off slightly (20mbar), will check it out better tomorrrow.


Here's a quick overview of the test:
Warm up engine to above 85°C (185°F)

View Measuring Value Block grooup 93, channel 2 in deceleration mode from approximately 2300 RPM to 1800 RPM in 5th gear (manual or Tiptronic).

Deceleration is indicated when channel 1 looks as follows: 00000100.
Desired value for channel 2 = 0.95 – 1.05.

Tip:3rd or 4th gear may be used if 5th gear operation causes road speed higher than local speed limit. Take an average of MVB93, channel 2 value.

Greater than 1.05
Intake leak between MAF sensor -G70- and Turbocharger
Crankcase breather hose disconnected or leaking
Exhaust Gas Recirculation (EGR) valve -N121- stuck open
MAF sensor -G70- out of tolerance or electrical problem in it’s circuit
Charge Air Pressure sensor -G31- out of tolerance or electrical problem in it’s circuit
Intake Air Temperature sensor -G72- out of tolerance or electrical
problem in it’s circuit
Cam timing incorrect
Exhaust restricted/plugged

"I'd like to thank Jeff for providing the TSB #. With that info and the p0101 code, I got back on Ebahn and found it. There's a wealth of information available to you on Ebahn with your subscription. I was unaware there was so much there.

Technical Bulletin 01 07 46 May 7, 2007 2010352"


I have an e-Bahn subscription too and all I find (under "diesel injection") are these:

23-05-02, Runs Rough on Initial Start on Temperatures Below 7 Degrees.....

AND

23-03-01, Poor Throttle Response (This one is for engine ALH)

Nothing else comes up. I can not sort by TSB number, either.

I wonder if I need to update something to get newer TSBs through e-Bahn. Any idea?

--Nate

PDJetta said:

I have an e-Bahn subscription too and all I find (under "diesel injection") are these:

23-05-02, Runs Rough on Initial Start on Temperatures Below 7 Degrees.....

AND

23-03-01, Poor Throttle Response (This one is for engine ALH)

Nothing else comes up. I can not sort by TSB number, either.

I wonder if I need to update something to get newer TSBs through e-Bahn. Any idea?

--Nate

Click to expand...

Try searching with P0101 and BEW. Search with all words.
Should come up as first item.

Figured it out. I had 30 minutes of updates to download from from e-Bahn. I thought the TSBs were on their server and that the content did not need updating.

--Nate

Pitboy said:

Pulled the EGR out again, it closes off completely. Anti shudder valve is not stuck either.

Any suggestions as to what would cause the EGR duty cycle to jump to 100% at WOT?

Click to expand...

I've been rounds on a couple cars. The tech line bloaks were adamant that you can't clean these EGR valves and have them work reliably. Either it's clean or you replace it. The moment I mentioned cleaning it they jumped down my throat about how that won't work and the car will still have problems. At least one gent referred to other cases where cleaning the valve showed minimal improvement while replacement fixed the problem.

I'm sure someone will jump in on they're soap box about how they're just company whores getting us to throw more parts at the cars on the customers' dime. But all the cars I have had this issue were VW's dime. And I figure the guy on the other end of the line has probably dealt with several other techs with the same issue.

Sorry about that, I'm putting the soap box away now

Jason

PS; I have another idea to isolate the issue. Could you try replacing the gasket on the upper EGR pipe with a blank. That would block the flow and you can see if the drivability improves. If it does then likely the EGR valve is at fault. Just a diagnosis idea.

I would like to add that where it says " MAF sensor -G70- out of tolerance or electrical problem in it’s circuit" If for any reason you replace the terminals to the MAF or any other sensor and the wires are twisted. You must twist the new wiring in the same manner that it was from the factory. Ecspecially on the PD's MAF. If you do not you may have fixed the terminal issue but it will cause all kinds of other issues because of the magnetic field the wiring creates by not being twisted.

Pitboy said:

I'd like to thank Jeff for providing the TSB #. With that info and the p0101 code, I got back on Ebahn and found it. There's a wealth of information available to you on Ebahn with your subscription. I was unaware there was so much there.

Technical Bulletin 01 07 46 May 7, 2007 2010352

My deceleration value from measuring block group 93, block 2 is higher than the upper threshold value of 1.05, with an average value of 1.19.
So far, the cam timing, breather hose, IAT(G72), MAF are good. Charge air pressure (G31) is off slightly (20mbar), will check it out better tomorrrow.


Here's a quick overview of the test:
Warm up engine to above 85°C (185°F)

View Measuring Value Block grooup 93, channel 2 in deceleration mode from approximately 2300 RPM to 1800 RPM in 5th gear (manual or Tiptronic).

Deceleration is indicated when channel 1 looks as follows: 00000100.
Desired value for channel 2 = 0.95 – 1.05.

Tip:3rd or 4th gear may be used if 5th gear operation causes road speed higher than local speed limit. Take an average of MVB93, channel 2 value.

Greater than 1.05
Intake leak between MAF sensor -G70- and Turbocharger
Crankcase breather hose disconnected or leaking
Exhaust Gas Recirculation (EGR) valve -N121- stuck open
MAF sensor -G70- out of tolerance or electrical problem in it’s circuit
Charge Air Pressure sensor -G31- out of tolerance or electrical problem in it’s circuit
Intake Air Temperature sensor -G72- out of tolerance or electrical
problem in it’s circuit
Cam timing incorrect
Exhaust restricted/plugged

Click to expand...

Well, changed out the EGR today, no running improvement other that it doesn't set the P0101 code now. Still low on power, still hesitates/rough in the 2000-3000 rpm range....

Do you have a vaglog of field 003? Is the maf capable of reporting air flow variation? You can hook up a shop vac and pull air thru and log this air flow too, it should give 1275. Perhaps there is another sensor on the power chain that is shorting and pulling the supply voltage down. Maybe check the manifold vaccum actuator that pulls the low speed intake restriction flaps. A bad alternator can throw voltages around enough to give intermittent faults too.
Jeff

The MAF appears to be functioning ok. Tried wiggling the connector to see if I got any variation with that. Of course there was no variation, as that would be too simple to find a bad connector.

you need to figure out if it's an electrical anomoly, or physical interruption in air flow. Both will give similar faults. vaglog the airflow and it should report steady request-vs-actuals. vaglog with air flapper disconnected and also with egr disconnected and watch the airflow behavior. Plot the data (or send it to me) and it will tell you whats going on. I have a wierd one now that reports reverse flow sometimes with steady state flow. that one is a bad driver in the ecu I believe. I have seen the airflapper fail where it actually shuts too much while running, like it's position sensor is out of calibration. Try to reset defaults in adaptation, you login with maintenance login 12233, but in the lower right pic box, i think advance settings, not the normal immo login pickbox. go to field 00 and test/save to reset defaults.
Jeff

ps. I once had a gas car that had a big plastic label blowing around in the cold air intake. It would get sucked up against the maf sensor and kill the air flow, then fall back down when turned off and car idled great. I think the mechanic working at the shop got fired over this car, they replaced many parts and blamed it on the tuning. It was an easy find when I studied the maf logs both connected and unconnected. vagcom is a wonderful tool! btw, I later called injen and complained to them not to put their labels inside the intake pipes - duh!

futher - they have good intake pipes compared to others, the diverter valve air port is far away from the maf, and doesn't interrupt the air flow in the pipe. I've seen some pipes where the DV inlet is located near and pointed directly at the maf. Guess what happens when the diverter valve opens and a blast of air hits the maf - dohhhh! maf-cel! Many aftermarket parts suppliers have no engineering skills and make pretty parts that look good but don't work worth a crap, let the buyer beware!

Jeff you have a PM.

Did you come up with a fix? I'm having the same problem.

So far I have replaced the MAF sensor, EGR valve, checked timing, checked the cat to make sure it wasn't plugged, and checked all the turbo tubing for leaks.

Never heard back on it. Car was taken out of state and sold.

I have the same problem with 2005 new beetle tdi. Have check timing which is 2.5 kw according to the baum scan tool. I should be 0-2
Have test everything in the bulletin and have not come up with a solution.
Have you found out any more on you 2005 jetta (pitboy)?

I would like to add that where it says " MAF sensor -G70- out of tolerance or electrical problem in it’s circuit" If for any reason you replace the terminals to the MAF or any other sensor and the wires are twisted. You must twist the new wiring in the same manner that it was from the factory. Ecspecially on the PD's MAF. If you do not you may have fixed the terminal issue but it will cause all kinds of other issues because of the magnetic field the wiring creates by not being twisted.

Click to expand...

Magnetic fields ? Come on ..
Check the hose on the intake , maybe the clip wore out the "ears" on the pipe and it's loosing boost.
It can also be poor grounds , too. I used to get the same error along with some GP errors, beefed up the grounds, have not seen a CEL yet but winter will ultimately tell.
Was the MAF cleaned at all ?

bmwmotorsports said:

I have the same problem with 2005 new beetle tdi. Have check timing which is 2.5 kw according to the baum scan tool. I should be 0-2
Have test everything in the bulletin and have not come up with a solution.
Have you found out any more on you 2005 jetta (pitboy)?

Click to expand...

I took the car to Botzons Automotive in Spokane and they were tenacious enough to track down the problem with my 05 beetle. Good on them!

The shop had installed the wrong MAF sensor. It took days to find the problem.

foxwell scanner codes

schwaben foxwell scanner,04 jetta tdi.would like to change egr and fuel quanity.the 12233 gets me in to adaptation,but none of the 33768 values work.