Diagnosing and Fixing Limp mode for A4 1.9TDI [low power troubleshooting]

[tnteggroll]

Ah lol tom hope it all works out

Haha, thanks Eric.

Got the new one, rang me in at $140, no PST. Got it installed about 30mins ago, took it for a test run and did well. Seems to have a bit more power, and i can hear the turbo, which i dont think was the case before. Took it on the highway, hit 160, and no limp-mode. Hopefully this took care of the problem.

On a side note, the trip to Edmonton seems to have un-seized my calipers. Possibly the heat from such a long trip?

 

[jheight]

first time posting

but i have spent hours reading through the forums trying to fix my car

99.5, tdi, golf, 292k
I get the code p1550(charge pressure deviation) when i scan.
i have replaced vacuum lines, cleaned intake(helped restore a lot of the power) and just switched the solenoids but i am puzzled with what i am supp0osed to look for after switching?

I still experience limp mode above 3k rpm in 3rd and the rpm's get lower in the higher gears..... always different depending on the hill and what not.
my n75 is a pierburg(not sure if those were the problematic ones or the good ones?)
so as you can tell im flustered and could really use some help
TIA

 

[doc_m]

Haha, thanks Eric.

Got the new one, rang me in at $140, no PST. Got it installed about 30mins ago, took it for a test run and did well. Seems to have a bit more power, and i can hear the turbo, which i dont think was the case before. Took it on the highway, hit 160, and no limp-mode. Hopefully this took care of the problem.

On a side note, the trip to Edmonton seems to have un-seized my calipers. Possibly the heat from such a long trip?

I'm thinking the braking that was needed going over the passes and through the mountains could have loosened up the pads, think they were stuck on there good.... perhaps the PO did not lube up where the carrier and pads meet and the brake dust just kept piling up....

 

[Canadian_Grizzly]

but i have spent hours reading through the forums trying to fix my car

99.5, tdi, golf, 292k
I get the code p1550(charge pressure deviation) when i scan.
i have replaced vacuum lines, cleaned intake(helped restore a lot of the power) and just switched the solenoids but i am puzzled with what i am supp0osed to look for after switching?

I still experience limp mode above 3k rpm in 3rd and the rpm's get lower in the higher gears..... always different depending on the hill and what not.
my n75 is a pierburg(not sure if those were the problematic ones or the good ones?)
so as you can tell im flustered and could really use some help
TIA

Swapping them out and still getting limp mode tells you that the N75 is good. I assume you checked or replaced all the vacuum lines? If not start there then check the diaphram on the actuator.

 

[alien_tdi]

hey guys - my 02 golf was going into limp mode yesterday after a long trip from albany to nyc and back - but no celo or faults - and n75 switching valve and turbo seem fine although when its real hot i seem to stop hearing turbo whisle. i know there arent any vacuum leaks and i recently cleaned my intake and did air filter and fuel filter, it also wont smoke even at wot at 4200 rpm. imgoing to try cleaning out my intercooler but i really dont know what else to try, any suggestions?

 

[Canadian_Grizzly]

and n75 switching valve and turbo seem fine although when its real hot i seem to stop hearing turbo whisle. i know there arent any vacuum leaks

If turbo stops working when its really hot, I would suspect collapsing vacuum lines. Have you replaced the stock ones and if so were they rated for vacuum?

 

[jheight]

Swapping them out and still getting limp mode tells you that the N75 is good. I assume you checked or replaced all the vacuum lines? If not start there then check the diaphram on the actuator.

I just replaced all the vacuum lines yesterday, and after switching the n75 there seems to be no difference....
How exactly do i check the diaphram on the actuator?(its buried on the bottom of the car correct? With the one vacuum line sticking out the bottom?)
The actuator itself seems to be in rough condition.... rusty and old looking... crap pealing off the outside....
is there an easy way to remove it? or is there a vacuum test that can be done to check it specifically?

Thanx again for the help

Update - I did a vacuum test on the actuator and it help 20 psi stead no problem

 

[Canadian_Grizzly]

Update - I did a vacuum test on the actuator and it help 20 psi stead no problem

How freely does the actuator rod move and what range does it go with vacuum applied. Might be time to look at Drivbiwires sticky vane thread contained in the writeup.

 

[Joeviocoe]

I just bought this 99.5 Jetta TDi with 198,000 miles and before I bought it, it had the CEL on and the VW place in Lakeland said it was for a MAF sensor and they were waiting to for the part to arrive. It did arrive and they have installed the MAF sensor along with glow plugs. When I got back down to Lakeland to buy it from Orlando, the CEL was off and it ran fine, so I bought the car. 3 days later (250 miles) and only 40 miles after my first fill up with ULSD from HESS, the CIL came on, and I noticed lack of power.

I am assuming this is the Limp Mode. The noticeable power loss (low RPMs but no sputtering or stalls) comes and goes now but the CEL comes on after about 15 secs after engine start and stays on. If something trips this Check Engine Light, is it supposed to stay on until a computer clears it or does it clear itself after the engine is turned off?

If you think you know what this could be, let me know (MAF, Turbo, N75 solenoid, air filter, fuel injector system)? I will settle for what you think it IS NOT.

Any help would be appreciated thanks.

 

[ymz]

Could be from a number of causes...

You need to get the CEL code read... even a generic (free) AutoZone scanner will probably do... Vag-Com is much better (look up UserID "GBangs" who's from Orlando...

All the best,

Yuri.

 

[Joeviocoe]

I read the code and it WAS for the MAF sensor again so the place I bought it from will replace the new sensor under the part's warranty.

Also an EGR code was on there too.
When the CEL first came on, I checked under the hood "while the engine was on" and wanted to rev the throttle from the engine (what I thought was the throttle). It was a small lever on the top right of the engine cover.

I think that is the EGR valve RIGHT?

I pressed it until the engine sounded like it was about to stall (a couple times). I didn't know (Newbie). Did that cause my EGR fault given by the computer (VAG-550)?

 

[rdkern]

anti-shudder valve?

 

[Joeviocoe]

yeah.. anti-shudder valve... I played with it while the engine was on... could that have given me the extra EGR code?

 

[rdkern]

It's job is to stop the engine. Don't know about the egr code.

 

[Joeviocoe]

038906018EB 1.91 R4 EDC G000SG 2143
CODING 00002 WSC 00066

2 DTC RECOGNIZED

16485 P0101 035
MASS OR VOLUME AIR FLOW CIRC.
RANGE/PERFORMANCE

17811 P1403 035
EGR FLOW
DEVIATION

The MAF sensor was replace only 3 days before the CEL came on for this. Im going back for a new one.

Could pushing the anti-shudder while the engine was on cause the "EGR Flow Deviation" fault?

 

[KarlM]

My '97 Jetta generated a P1550 code several years ago with the engine going into limp mode every time the MIL came on. I replaced the N75 but that wasn't the problem. I eventually discovered the pressure pipe attached to the intake manifold - it connects on the other end to the hard pipe leading back to the intercooler - had ruptured on the back side, out of sight. It was the last thing I would have thought of and it was pure luck that I found it as quickly as I did. I don't know if that helps anyone, but it's darn easy to check!

 

[TurbineWhine]

Yes, a clogged cat could cause it...

Ok, car is an 01 Golf TDI with 129K miles. The car has been running without an Intercooler & MAP sensor, in permanent Limp Mode, for the last 6 months. No the car does not belong to me. I replaced all the missing parts and now the car runs great up to the point that it goes into limp mode. All vacuum lines are good, actuator does not leak, intake has been cleaned and the turbo vanes move freely. The Vag codes are:

VAG-COM Version: Release 607.3-UD
Control Module Part Number: 038 906 012 CP
Component and/or Version: 1,9l R4 EDC G100AG 2839
Software Coding: 00001
Work Shop Code: WSC 05087
3 Faults Found:
19561 - Valve for Intake Manifold Flap (N239): Open or Short to Ground
P3105 - 35-10 - - - Intermittent
17964 - Charge Pressure Control: Negative Deviation
P1556 - 35-00 - -
16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal
P0106 - 35-00 - -
Readiness: 1 2 0 0 1

The first fault is due to the installation of a DG RacePipe without a RocketChip remap.

I am wondering if the CAT is stopped up from all the time running in limp mode. The car does seem to run with close to normal power until it hits limp mode at high revs.

Thoughts or suggestions?

TW

 

[TurbineWhine]

Found and fixed the problem. Rather simple actually so naturally it took a long time to find it. The MAP plug was missing so I was having to hard wire in the MAP sensor. I had the 4 wires reversed, left to right. Put them in the correct left/right order and the problem and codes were resolved.

TW

 

[Fathom]

My turbo works perfect, I just cleaned it out, put a ndw actuator on it and also changed the solenoid with the white top on it bolted to the fire wall. The weird thing is the light comes on almost immediatly after starting the car, when the car is in over boost, it will come on when you are abusing it. Hmm dont know

 

[alphaseinor]

fathom, check the vacuum lines... especially the one coming out of the vacuum pump to the brake booster.

 

[Ann]

99.5 A4 Jetta no boost. Started very intermittant then slowly advanced until all the time. Read post, swapped relays (?) at N75 - inside black box next to airbox on driver's side firewall - two small gray boxes that say "53" on them. That seems to have fixed the problem. (more testing tomorrow)So now which one is the bad one? Inboard or outboard or just buy two new ones? And how long can I drive with the swapped parts until new ones arrive?

I love this place!

 

[Ann]

Hmmm....OK so I didn't touch the N75 valve (looked at photo on tdiparts.com) but that box with the two gray 53 relays must have something to do with that system. Went for a little longer drive (roundabouts!) then stopped and swapped back relays and still works great. Dunno what "fixed" itself - but now I'm not afraid to get back on the interstate....

Any ideas anybody?
Thanks!

 

[jonjon]

Would this apply to the A5 Jetta?

Reading this fix my A5 is doing the exact same thing, along with another guys up in Utah. Both our cars have been at the dealer for at or over a month and his has had multiple EGR valves and still no fix. Mine got a free Mechatronics unit for the DSG during the mis diagnosis and is now awaiting a long backorder on the EGR valve..Methinks this new valve isn't gonna fix it and I am 800 miles from my car so can't run out there to check on it..I printed out and started to fax over the instructions listed here to my service guy but figured the emission system on the A5 is probably so different this might not apply..
Thanks,
John

 

[Miyagi]

my cars (01 Jetta TDI, 01 Golf TDI) went into limp mode around 60K and 70K miles respectively. It was a bad MAF sensor for both cars. CEL did not come on for a couple weeks while in limp mode. I was not near a dealership, so found a MAF ($75 typical) online and 2 minute fix did the trick.

 

[Blackburn]

I experienced the same loss of power at 70 mph uphill and it would do it consitently. Then would be fine after I cycled the ignition. I changed the fuel filter and it never did it again. Could it be that a restricted fuel filter could cause limp mode when the pump asks for more that it can draw from the filter?

 

[Joeviocoe]

I'm going to add a little bit to this... btw... great writeup

Limp mode is best described as a complete loss of turbo power, when you key off and key back on your power should be back,
If this is not your symptom, you should check the MAF 101 page... which just says unplug your maf, and if it's better or the same, then it's bad.

I think you should scan the car first...

There are three common codes for limp mode.
Boost Deviation Intermittant
Boost Deviation Negative
Boost Deviation Positive

Boost Deviation Intermittant means you most likely have a vacuum leak somewhere. Check all lines, actuators, and plastic fittings.

Boost Deviation Negative means you have a clogged intake, actuator that's leaking, bad vacuum lines, or a sticky turbo.

Boost Deviation Positive means you have a N75 that's bad/malfunctioning, actuator that's leaking, bad vacuum lines, or a sticky turbo.

In addition... the A3 and B4 models (1998 and older, jetta, passat) have a Vacuum line in the ECU... but basically the same procedure... They run on boost, not vacuum, so a tire pump may be of use to see if the actuator is working on the turbo.

My DTC:

VAG-COM Version: Release 409.1-US
Control Module Part Number: 038 906 018 EB
Component and/or Version: 1,9l R4 EDC G500SG 2143
Software Coding: 00002
Work Shop Code: WSC 00066
1 Fault Found:
17958 - Charge Pressure: Control Deviation
P1550 - 35-00 - -

is this
Boost Deviation Intermittant or
Boost Deviation Negative or
Boost Deviation Positive???

I was having this code with limp-mode all the time when I run it with high load (accelerating up hill or too hard). About once or twice a day and much worse on hot days being in the heat.

MAF sensor replaced new (correct for my ALH engine, not the 2.0) This solved the P0101 codes. Confirmed by my Vagcom.
Fuel Filter replaced, Intercooler cleaned out (lot of oil in there).

I have cleaned out the EGR and replaced its gasket... it solved my P1550 errors 90% of the time (gasket looked to be leaking). So now I only get it when it has high load for more than 5 secs (approx).

Right now, I have less than acceptable power, poor fuel economy (36mpg max even when watching the SGII carefully), NO SMOKE even when pushing hard, and the P1550 Charge Pressure: Control Deviation code when sustained WOT with load (SGII showing 35psi) for more than a few seconds.

My Scangauge II shows max. sustained MAP readings at 35psi (20psi boost). Seems too high. But when it goes into limp mode and gives me the P1550, I don't know if it is a intermittant, positive or negative deviation.

I have played with the N75 with VAGCOM group 11 basic settings (10sec cycle for N75 solenoid, and the turbo acuator seems to move the proper amount (about an inch). (I drive it too hard to be the vanes sticking from built up soot). Next would be to either swap the N75 (white top) with the EGR solenoid (black top).

Does anybody know how much vacuum (in psi) is normal for the N75 line to the turbo actuator? I guess I can buy a vacuum tester and check the meter but I need a good reference psi number.

Please help. Thanks
-Joe

 

[Zitro]

Great write-up CG... saved me a trip to stealership. The Jetta went into limp mode 1 day after I did the timing belt change. The brakes felt stiff also. Naturally I thought it was something I did with the timing belt change procedure. CG's write-up says check the vacuum hoses. I did, and found the hose to the component right below the EGR was off at the firewall. Must have come loose when I lowered the engine to remove the engine mount bolt. Runs like a champ now. TDI Club rocks!!!

 

[Zitro]

Forgot to mention, the code it through when it went into limp mode was
17964 - Charge Pressure Control: Negative Deviation
P1556-35-10- --Intermittent

The problem was an unplugged vacuum line.

 

[power4ever]

Hi

Do you have a adres for me were i can find a racepipe that fits on my golf4 with a upgraded intake manifold from a ARL version. The problem is that it sweats/leaks a little by the EGR . It comes from the little hole under the cirkel(UFO). Thats why i am looking for a racepipe.

Looking forward to your reply`s

Please mail me

Regards Jim


http://pics.tdiclub.com/showphoto.ph...72&si=racepipe

 

[Turbosprezarka]

Here's another scenario which I'm having. I ran the Block 11 test with Vag-Com, heard the N75, and saw the VNT actuator moving fine. But when I connect a hand vacuum pump to either the vacuum line connected the the actuator, or the actual nipple on the actuator itself, it will NOT hold vacuum and will NOT move the actuator rod.

I know the hand vacuum pump works fine because I tested it on other hose connections, and can verify I'm making a good seal on the actuator.

I also do not have any stored codes, but boost does seem to be more laggy than it used to be, based on my boost gauge in the cabin.