www.tdiclub.com

Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You

Order your TDIClub merchandise and help support TDIClub


Go Back   TDIClub Forums > FAQs (Frequently Asked Questions) > TDI Maintenance

TDI Maintenance Archives on TDI Maintenance related items.

Reply
 
Thread Tools
Old December 29th, 2012, 15:48   #376
vtveg
Veteran Member
 
Join Date: Jun 2008
Location: VT
Default

Diagnostics question:
03 has had over-boost issues since we bought it this summer, which have gotten slowly worse. Car is generally pretty gutless, but definitely has the limp mode thing going -> definite loss of power if you ask too much from it and then its absolutely useless (like slowing to 45 on a big hill on the interstate.)

Finally borrowed a vacuum gauge from a friend today. With the car idling at startup,
26 inhg at the hard line.
26 inhg at the going to the vac port into the n75 valve, which held for 10+ minutes after the car was shut off.
steady 14 inhg coming out of the out port on the n75 regardless of my wife revving car

Based on this I'm guessing that the issue is a dud n75 valve which isn't correctly modulating the vacuum to the actuator. It was my understanding, although I can't tell you from where that the n75 valve should at idle supply the full 25"hg? Am I off my rocker?
__________________
2003 Jetta Wagon stock Auto never veg'ed.
vtveg is offline   Reply With Quote
Old December 29th, 2012, 19:18   #377
whitedog
Veteran Member
 
Join Date: Jul 2004
Location: Bend, Oregon
Default

Vacuum gauge won't tell you much beyond the fact that you have vacuum. Just sitting and revving won't cycle the turbo since it needs a load. You could tee in and use a long vacuum hose to watch vacuum to the actuator or just get a vacuum pump and cycle the actuator that way. Often, if the bottom engine cover is missing in the salt states the actuator rusts out. You need to see if the actuator moves, when it moves, when it stops and if it holds vacuum.
__________________
Can rent movies at BlockBuster.
whitedog is offline   Reply With Quote
Old December 30th, 2012, 09:00   #378
rdkern
Veteran Member
 
Join Date: May 2004
Location: Humboldt Co CA
Fuel Economy: A4 = wife drives it, don't know
Default

I would think that the N75 valve is having a problem. It should provide you with the same 26 at the hose going to the VNT that you're getting at the input to the N75.

Did you try to move the VNT actuator with vacuum? As whitey says, it should move and keep the vacuum for quite a bit.

Do you have VCDS? If so, you can test this again, with the VCDS telling the N75 to open and close the VNT, which, with the vacuum gauge, you can see if the N75 is responding correctly.

If I were in your situation, and didn't have VCDS, I would swap out the N75.
__________________
Whitedog's in progress no-start link. http://forums.tdiclub.com/showthread.php?t=199398
Read all about it!
rdkern is offline   Reply With Quote
Old December 30th, 2012, 12:05   #379
whitedog
Veteran Member
 
Join Date: Jul 2004
Location: Bend, Oregon
Default

You can also swap the two solenoids back there. One runs the VNT, one runs the EGR and even though they are different colors, they work just the same.
__________________
Can rent movies at BlockBuster.
whitedog is offline   Reply With Quote
Old January 15th, 2013, 10:09   #380
mecne
Veteran Member
 
mecne's Avatar
 
Join Date: Sep 2011
Location: Brighton - Oshawa Ontario
TDI(s): 15 Jetta TDI
Thumbs up no more Gutless Golf

Thanks for this amazing Guide ..

Just finished troubleshooting (started a week ago) and fixing my Turbo Issue on a 2000 Golf I bought a few weeks ago. I knew when I bought it , that it had a turbo issue .. how could ya not by driving them without a working Turbo.
Vagg'd it before I bought it as well and with the code below.
Code -
1 Fault Found:
17964 - Charge Pressure Control
P1556 - 35-10 - Negative Deviation - Intermittent
Log Graph of before .


Boost Actual Yellow line .. not much movement there..

1- Tested Actuator with mighty vac .. ( A must when doing this) not holding vacuum.
2- Tested and pulled an actuator off a turbo I had in the Shed.
Change it and run new vac hose .. Test from up top and movement at -5 inHg, and be on the stop (fully open) at 18 inHg. All good ..
3- Connect and start the car .. Vag into Engine , Basic Settings and 011 .. got small movement .. DOH!!!
4- Swap the N75 from one I had in the shed .. Nothing .. Mighty Vac top vac line .. Nothing ..
5- Start replacing Vac hoses .. break the nipple off on the hard vac hose from the Pump to the Brake booster .. DOH!!!!!!!
6- Back to the Shed ..
7- Replace the Hard Vac hose .. connect Mighty Vac .. and bam .. 25 inHg on the gauge .
8- Button everything up ..
9- back to Vag with Basic Settings 011 .. Full range of movement .. and can hear the pressure difference ..
10- Test Drive .. that's the way it's suppose to pull ..
Bingo bango bongo .. All fixed ..
Log Graph of After
__________________
M
15 Jetta TDI
10 MB ML350 Bluetec
mecne is offline   Reply With Quote
Old February 7th, 2013, 16:52   #381
CWI_TDI
Member
 
Join Date: Jul 2008
Location: Hollister, CA
Fuel Economy: 150k mi, 41mpg
Default

Would anyone have a theory about outside air temp and limp mode frequency? My experiences are that it drops into LM when the temp is 35+/- 5 deg F but in the afternoon, as much as I try, I can't get it to do the same. I commute 70 mi one way in NorCal and have a fairly steep, approx 2 mile incline, where it occurs most often-and more often when traffic forces me to slow down below 2500 rpm and then try to accelerate. Often traffic allows me to do the return trip(opposite incline) up thru 80+ mph without any issues in the afternoon. It throws a P0234 code when it goes into LM. I cleaned the MAF last summer w/MAF cleaner and seemed to help at the time. Just wondering if isolating temp as a factor could lead me to a faulty component.
03 TDI ALH, 188k mi
Thanks for looking.
__________________
2003 Jetta, Plat Gray
North American AT-6D, 4.6 mpg
99 GMC Suburban

Radial engines don't leak oil, they're just marking their territory.
CWI_TDI is offline   Reply With Quote
Old February 8th, 2013, 13:08   #382
MCR
Veteran Member
 
Join Date: May 2007
Location: Cincinnati, Ohio
Default

@ CWI_TDI: That is an overboost code. So, yeah, the colder air is higher density, and would be easier to overboost than a higher temperature afternoon trip. I'm no guru, but I would look get a Mityvac and verify that the VNT actuator (a vacuum actuator with a nipple that faces downward attached to the turbocharger) has free motion. Also, the vacuum line could be leaking and need to be replaced. The VNT Vanes are normally in low speed position, and move to reduce boost as the boost grows. Yours are probably not moving as the boost grows. Options are (1) actuator is leaking (rubber bladder cracked?), (2) vacuum line is off or leaking, or (3) the linkage is rusted and needs to be moved and lubed.
MCR is offline   Reply With Quote
Old February 9th, 2013, 19:55   #383
JohnnyChimpo
Newbie
 
JohnnyChimpo's Avatar
 
Join Date: Feb 2013
Location: Colorado
Fuel Economy: mid-40s
Default

Anybody know if a code P0135 HO2S heater circuit fault will cause a limp mode? Got an '04 Golf BEW that has no power, will only idle and has this code. Happened at the same time the lift pump failed. Weird.
JohnnyChimpo is offline   Reply With Quote
Old February 13th, 2013, 15:40   #384
CWI_TDI
Member
 
Join Date: Jul 2008
Location: Hollister, CA
Fuel Economy: 150k mi, 41mpg
Default

Sorry, maybe a dumb question but if I pull 20in vacuum at the actuator and it drops to 15in about 10 mins, is that considered a leak, or, is that a generally accepted drop in vacuum, or, should it hold indefinitely? ( I read all 26 pgs of this but I don't think it's been specified)
If a leak...then could someone share a technique on how to get the e-clip off the actuator..(more importantly, how to get it back on)...any special tools, mini- needle nose, picks...a 3rd an 4th arm, etc...without pulling the intake, etc? thanks again
__________________
2003 Jetta, Plat Gray
North American AT-6D, 4.6 mpg
99 GMC Suburban

Radial engines don't leak oil, they're just marking their territory.
CWI_TDI is offline   Reply With Quote
Old February 13th, 2013, 18:36   #385
whitedog
Veteran Member
 
Join Date: Jul 2004
Location: Bend, Oregon
Default

Get a big, white sheet and put that under the car. Use a pick to remove the clip. Find the clip on the sheet, somewhere.
__________________
Can rent movies at BlockBuster.
whitedog is offline   Reply With Quote
Old March 26th, 2013, 08:04   #386
Stopp700
Newbie
 
Join Date: Mar 2013
Location: North Kingstown, RI
Default

Canadian Grizzley, thank you for explaining in detail the cause(s) for Limp Mode in the TDI Jetta. After dicussing this with my mechanic and showing him your explanation on how to fix the problem it was easy for him to figure out that I had a bad Actuator. Just like you said the VW Dealers did not want to sell just the Actunator. He ended up buyiing one from a parts store on the West Coast. Saved big bucks!!! Thank you again!
Stopp700 is offline   Reply With Quote
Old April 2nd, 2013, 11:44   #387
flashmayo
Veteran Member
 
Join Date: Apr 2007
Location: Santa Cruz CA
Default

One thing I learned troubleshooting a limp mode issue over a couple of years is that if your ECU is not getting a good clean reference voltage it will cause you all kinds of headaches. I found this when the battery that my car came with got old enough to cause slow cranking in the blistering cold of a CA morning. Replacing the battery has eliminated any sign of limp mode. Of course I had replaced vacuum lines, cleaned intake, replaced MAF, replaced N75 etc in the course of troubleshooting the issue.
So, check your charging system and grounds, and verify that your battery is the proper battery for the 1.9.
flashmayo is offline   Reply With Quote
Old May 17th, 2013, 14:07   #388
pandsa
Newbie
 
Join Date: Oct 2006
Location: Moose Jaw
Default Looking for tdi guru for turbo repair

Cel is on and have p1556 and p1557 code. Looking to find a good mechanic in Saskatchewan for help with repairs. Does anyone know of one or where there may be someone close. Thx.
pandsa is offline   Reply With Quote
Old July 10th, 2013, 18:32   #389
Krytie TV
Member
 
Join Date: Jun 2013
Location: Detroit
TDI(s): 2006 Jetta
Default

From reading the OP, am I to understand that a disconnected hose at the bottom of the air cleaner container can cause an overboost enough to shut down the turbo?
Krytie TV is offline   Reply With Quote
Old July 11th, 2013, 09:01   #390
rdkern
Veteran Member
 
Join Date: May 2004
Location: Humboldt Co CA
Fuel Economy: A4 = wife drives it, don't know
Default

Are you talking about the one from the air filter to the N75? That just provides "clean" air to the system when the switch wants to close the VNT system. You might get some dirt in that way which could wreck the N75. Just the disconnect shouldn't cause an overboost.
__________________
Whitedog's in progress no-start link. http://forums.tdiclub.com/showthread.php?t=199398
Read all about it!
rdkern is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Diagnosing and Fixing Limp mode for A4 1.9TDI [low power troubleshooting] Canadian_Grizzly TDI 101 600 June 13th, 2019 12:23
Audi A4 Low power and limp mode and other problems arijus TDI 101 5 August 9th, 2018 15:34
Low power,limp mode vrus13 VW B5 Passat TDIs 6 October 30th, 2012 09:26
Low Power, no limp mode TDIBrandon VW MKIV-A4 TDIs (VE and PD) 6 February 27th, 2012 04:44
First time diagnosing low power / 1x/limp kiva822 TDI 101 35 July 30th, 2011 05:10


All times are GMT -7. The time now is 00:26.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
1996 - 2020, All Rights Reserved
Page generated in 0.15850 seconds with 11 queries
[Output: 126.63 Kb. compressed to 106.01 Kb. by saving 20.62 Kb. (16.28%)]