What did you do to your MKIV today?

dieseldonato

Veteran Member
Joined
Mar 10, 2023
Location
Us
TDI
2001 jetta
I've usually just assumed it goes away after a key cycle, I've only gotten an over boost code once, and it happened as I was rolling into the driveway, I had vcds logging already. So I backed put of the log and checked codes. Haven't ever seen it after a key cycle.
 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
If you scan it before turning the key off while in limp mode, the dtc will be present
It will be there after you cycle the key too.

As the go to guy for VCDS scans in this area for many years, I've had dozens of ALHs roll into my driveway with an overboost DTC flagged. None of them were idling when scanned, probably 60% had the CEL illuminated too.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
It will be there after you cycle the key too.

As the go to guy for VCDS scans in this area for many years, I've had dozens of ALHs roll into my driveway with an overboost DTC flagged. None of them were idling when scanned, probably 60% had the CEL illuminated too.
I’ve not run across the number you have, just the one instance with mine. IIRC In that case it was only present after I checked it without shutting it down
 

Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
Well, I scanned it with vag com when I got home, after two restarts (one to fix limp, second to drive home after work). No code. Took a log for burpod this morning.
 

dieseldonato

Veteran Member
Joined
Mar 10, 2023
Location
Us
TDI
2001 jetta
Well, I scanned it with vag com when I got home, after two restarts (one to fix limp, second to drive home after work). No code. Took a log for burpod this morning.
What year is your car? As I understand it there were differences between software in the 01 and earlier cars.
 

CanadianALH

Veteran Member
Joined
Aug 21, 2023
Location
Canada
TDI
2002 Jetta 5spd 2006 Jetta DSG (wifes)
My ALH overboosted three times before it tossed a CEL. I'd just drive and log it until it throws one.
 

Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
Well, I logged for Burpod; interested to see what he says. Of course, limp didn’t occur during that log, or on my drive home. I punched it a few times, especially going up hills, to see if I could hit limp again—nothing but sweet, sweet power. Maybe it was a fluke? I’ve owned and dailied it for 3 years now, and this is the only time its ever gone into limp mode.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
I hear it happens to everyone eventually
 

csstevej

Top Post Dawg
Joined
Aug 12, 2004
Location
north nj
TDI
2001 golf tdi 4 door auto now a manual, mine, 2000 golf 2 door M/T son's,daughters 98 NB non-TDI 2.0, 2003 TDI NB for next daughter, head repaired and on road,gluten for punishment got another tdi 2001NB,another yellow tdi NB
Probably had a brain fart . 🤣🤣
 

dieseldonato

Veteran Member
Joined
Mar 10, 2023
Location
Us
TDI
2001 jetta
I'm assuming thats the difference then. When i hit over boost (which I think is 35 psi) car falls flat on its face and doest make boost till its key cycled. It's actually almost dangerous to drive, no power at all, even flat to the floor zero smoke, zero (well like 3 psi) boost. No cel.
 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
I'm assuming thats the difference then. When i hit over boost (which I think is 35 psi) car falls flat on its face and doest make boost till its key cycled. It's actually almost dangerous to drive, no power at all, even flat to the floor zero smoke, zero (well like 3 psi) boost. No cel.
Overboost isn't a specific value, it's a deviation from specified over time. IIRC, when actual exceeds specified by 300 mBar or more for 5 seconds, the ECU assumes the boost control system has failed and drastically cuts fueling to protect the turbo, aka limp mode. It's quite possible to hit limp mode at relatively low boost levels - 12 psi actual when 6 is requested will do it.
 

norbert77

Veteran Member
Joined
Feb 2, 2022
Location
Petrolia
TDI
01 beetle
I have experienced multiple limp mode instances with no CEL (pulled over and scanned after it happened). I have also had it throw a CEL, but of the probably 20+ times I've gone into limp, only 1 threw it
Mine often does that when the turbo vanes get sticky or carbines up
 

P2B

Top Post Dawg
Joined
Jan 11, 2006
Location
Toronto & Muskoka, Canada
TDI
2002 Jetta, 2003 Jetta, 2003 Jetta Wagon
My ALH overboosted three times before it tossed a CEL. I'd just drive and log it until it throws one.
There must be an algorithm to determine if the CEL is illuminated after an overboost, but it's not easy to figure out by observation. Pretty sure my MK3 did it every time.
 

dieseldonato

Veteran Member
Joined
Mar 10, 2023
Location
Us
TDI
2001 jetta
Overboost isn't a specific value, it's a deviation from specified over time. IIRC, when actual exceeds specified by 300 mBar or more for 5 seconds, the ECU assumes the boost control system has failed and drastically cuts fueling to protect the turbo, aka limp mode. It's quite possible to hit limp mode at relatively low boost levels - 12 psi actual when 6 is requested will do it.
I only get it above 2500 rpm, gauge hits 35psi car looses power. Logs confirm as well. Requested vs actual boost is off , and you can see the vane go full open and fuel is pulled too.
I hadn't realized it was a percentage of something, and thought it was a hard x psi/mbar.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Last week IBW got new rear rotors and pads, calipers, cables, and splash shield, which of course required new hubs and bearings.

Calipers and cables were original to the car. Not bad service life.
 

JDSwan87

Black Swamp Thing
Joined
Feb 9, 2014
Location
Michigan near Toledo
TDI
2001 Jetta TDI, 5 speed Lagoon Blue Metallic(sold); 2005 Jetta TDI Wagon auto
Last week IBW got new rear rotors and pads, calipers, cables, and splash shield, which of course required new hubs and bearings.

Calipers and cables were original to the car. Not bad service life.
I'll have to call your road commission and request dump truck levels of road salt to be applied in the winter...
 

CanadianALH

Veteran Member
Joined
Aug 21, 2023
Location
Canada
TDI
2002 Jetta 5spd 2006 Jetta DSG (wifes)
I'll have to call your road commission and request dump truck levels of road salt to be applied in the winter...
Makes such a difference. My car is 22 years old, has done 453k Km and still has some paint on the underside and the bolts like to come out. My sister has a 2011 Corolla with half the Km gas tank guard rusted through and was falling off as the car lived it’s life out east in Canada where they only use salt on the road. Happy to live in Alberta where the salt isn’t used as much.
 

CanadianALH

Veteran Member
Joined
Aug 21, 2023
Location
Canada
TDI
2002 Jetta 5spd 2006 Jetta DSG (wifes)
So, like, Saskatchewan? 😂 I think you guys are possibly the only province that doesn't salt lol.
BC doesn’t either. The BC cars in Canada are like California cars. They command like 2k more if you can prove it’s never left BC. But if you look out east they have Alberta cars and claim less rust on them as well. By buddy had a TL type S from BC and that thing was minty. There are auto Jetta wagons there for $12,000 cause the bodies are so darn nice.
 

J_dude

Veteran Member
Joined
Jan 9, 2020
Location
SK Canada
TDI
2003 1.9l “Jedi”
BC doesn’t either. The BC cars in Canada are like California cars. They command like 2k more if you can prove it’s never left BC. But if you look out east they have Alberta cars and claim less rust on them as well. By buddy had a TL type S from BC and that thing was minty. There are auto Jetta wagons there for $12,000 cause the bodies are so darn nice.
Hmm ok, didn't know that.
Too bad I didn't know enough to spray the crap out of my truck with Fluid Film after I brought it here from Kelowna. Now it's been here a couple of years and it's already rusting out. 😝 I was young and dumb back then lol.
 

CanadianALH

Veteran Member
Joined
Aug 21, 2023
Location
Canada
TDI
2002 Jetta 5spd 2006 Jetta DSG (wifes)
Hmm ok, didn't know that.
Too bad I didn't know enough to spray the crap out of my truck with Fluid Film after I brought it here from Kelowna. Now it's been here a couple of years and it's already rusting out. 😝 I was young and dumb back then lol.
When I was younger and dumber I bought a car from out east that needed work. Broke a bolt on that stupid thing everytime I tried to fix something, learned that everytime I went to pick and pull to take as many 10mm bolts as I could so I had spares. Also found out that fender liner bolts from a Nissan can be used to replace lost bolts on a VW oil pan cover last week.
 

J_dude

Veteran Member
Joined
Jan 9, 2020
Location
SK Canada
TDI
2003 1.9l “Jedi”
Anyone know where I can get a good 11mm pump in Canada?
Talked to Giles, he says he can build one for stupid money, but I don't need a built pump I just need a pump, and soon.
I could find a used one but I don't want to have to tear it down like KrashDH right now, I just want to throw it on and get this car going again.
 
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