Need DTC Help (not another glow plug thread)

WillR

Veteran Member
Joined
Mar 2, 2001
Location
Honey Brook, PA
The last couple days its been real cold, car starts fine. I run around 10 miles of back roads, car runs fine, warms all the way up. I hit the highway, within a couple minutes I seem to loose power, top speed maybe 60mph on flats.

When It first did this I discovered a restart clears the problem, which to me means its not fuel. Plus the fule is winterized by me and the dealer.

It did it again yesterday morning, so last night on the way home I hooked up VAG-com.

I have code
1 DTCs Found:
00575 - Intake Manifold Pressure
17-00 - Control Difference

where do I go from here?

It did it again this morning, but I did not have time to check the codes.

I can only get it to throw this code if its real cold, and I am pushing the car pretty hard down the highway (late for the train)

98 (late 97 build) Jetta.
 

VelvetFoot

Top Post Dawg
Joined
May 17, 2001
Location
Sand Lake, NY
TDI
NB, 2000, Yellow
It seems you have a turbo control problem. Maybe first try replacing the hose to the ECM (computer). Maybe then replace N75 control valve. Maybe.
 

WillR

Veteran Member
Joined
Mar 2, 2001
Location
Honey Brook, PA
So this code points more to
"the ECM did not see the results it expected" and not.

"the resistence of the sensor was out of bounds"

I assume I could watch this happen on the Mesuring blocks? I don't have a list of which block does what, but I would look (chart while driving) at a block that shows MAP expected and actual? But with the sample rate being slow, I guess I would not see it
 

VelvetFoot

Top Post Dawg
Joined
May 17, 2001
Location
Sand Lake, NY
TDI
NB, 2000, Yellow
This is what my long-distance diagnosis (
) would indicate. Quite a few other people have had the same problem here on the boards. I do believe you could see the lack of control the ECM sees on vag-com. If you do have vag-com you can run it through its diagnostic mode and see if the N75 is clicking, which , if it's totally dead won't click (I have personally seen this on someone's '98 Jetta). The hose, as I've said, is another likely suspect. The TDIFAQ does have a blurb on this issue: http://www.tdiclub.com/TDIFAQ/TDiFAQ-8.html#e
 

VelvetFoot

Top Post Dawg
Joined
May 17, 2001
Location
Sand Lake, NY
TDI
NB, 2000, Yellow
However, maybe the cold we're seeing is implicated somehow, like maybe water freezing in the N75 valve or the hose or something like that. MAYBE, especially if this is only happening in these cold temps.
 

John Beyer

Veteran Member
Joined
May 12, 2000
Location
Peninsula, Ohio
TDI
1998 White TDI/GT Jetta, 2003 Silver Jetta
The N75 uses pressure from the turbo itself to move the wastegate.

I've been having the same problem on my A3. The 1st thing I did was clean the oil out of the 3 lines to the N75 and the valve. The problem went away for 2 months. It came back so I cleaned out the wastegate actuator(there was more oil in the line to it) and tried some new clamps on the blue line(hose clamps this small are hard to find). It's been fine now for 2 weeks.
 

bowlerman

Veteran Member
Joined
Jul 31, 2001
Location
medford, NJ
TDI
2001 jetta tdi black
willr do you have the bentley manual? it shows you how to check everything its so easy! all you do is this the n75 on A3 is right near the MAF against the firewall has blue and red rubber hoses coming out oif it. take hoses off and make sure everything is clear and clean, then check the n75 itself! get a multimeter and check for 25 to 45 ohms resistence! if too much or too little than that replace it! u can do a number of tests. throught vag com you can do an output test and the thing will click, if n75 doesnt click then throw it out and get a new one. make sure the solenoid on the turbo are working, that also get clogged. one more thing, check MAF and make sure its reading the right mg/stroke, i think, on vagcom. hope this helps. also did u ever do the egr modification?? if not you intake may be clogging, check the intercooler for oil?? there is more if you want you can call me, 2034163175
 

WillR

Veteran Member
Joined
Mar 2, 2001
Location
Honey Brook, PA
Yes, I really think the cold has something to do with it. If the car sits in the parking lot at the train station, its still cold, but the sun will warm the car somewhat. and it only happens when I hit higher RPM's when its cold outside. I think my waistgate system uses vacuum to hold the waist gate closed, and lack of vacuum opens the waist gate, switched by the N75. Now if the n75 valve is sticking in the default position when real cold, I may be seeing high boost causing this code. Sound good?
 

go_tdi

Veteran Member
Joined
Jan 29, 2002
Location
fallsington, pa usa
TDI
12 Golf, 04 Jetta
WillR,

I’ve also been experiencing the same symptoms the last few weeks. I believe that is what lead to my turbo failure. I’ve been to busy (lazy) to hook up VAG to find out why check engine light is on. However I didn’t need VAG to diagnose the metallic whine coming from turbo….

In hind sight I belive that because of air density + air temp of 0 F the ECU asked the injection pump to do something it couldn’t . as far as my turbo failing… I heard to sound of rushing air for 15 seconds then the sound of the hot side turbine hitting the housing, followed by me muttering a long list of explicative deleted’s (#%#%&* *$% $$%^& *%$@!!!) at my own stupid self for not stopping!!!
 
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