Volkswagen Mark IV Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter · #1 ·
Hi all

My son has got a Golf 1.9 tdi mk5 (BKC) engine, now hes been having trouble with limp mode, anyway the fault

lies to the turbo boost solenoid, can anyone tell me the location of this solenoid on the engine, according to Haynes manual

its at the left of bulk head ? only solenoid I see there is the egr vacuum solenoid, the manual says not to confuse this with boost solenoid

but I cannot see this anywhere , further reading mention engines with particulate filter and non particulate filter... can anyone help me

with this issue ... am I wrong thinking that the egr vacuum solenoid which has 6 tubes leading to it could also be the boost solenoid combined ?

all advise/help much appreciated
 

·
Diesel Geek
Joined
·
4,089 Posts
If you have a black box with six or so vac lines coming from it you will have the combined n75 boost solenoid and n18 egress one. They suffer from leaks and failure.
 

·
Registered
Joined
·
4,574 Posts
Hi all

My son has got a Golf 1.9 tdi mk5 (BKC) engine, now hes been having trouble with limp mode, anyway the fault
lies to the turbo boost solenoid, can anyone tell me the location of this solenoid on the engine, according to Haynes manual
its at the left of bulk head ? only solenoid I see there is the egr vacuum solenoid, the manual says not to confuse this with boost solenoid
but I cannot see this anywhere , further reading mention engines with particulate filter and non particulate filter... can anyone help me
with this issue ... am I wrong thinking that the egr vacuum solenoid which has 6 tubes leading to it could also be the boost solenoid combined ?

all advise/help much appreciated
It's on LHS of bulkhead right next to the battery cover and is a multi-function solenoid with 6 hoses and feeds turbo actuator, EGR and brake servo

Photo, schematic and notes from VW factory ELSAWIN manual attached below

No need to worry about DPF, your engine doesn't have one

I've got a 07 1.9TDI Match with the later BXE Engine 105PS

Just curious why you think you have a faulty solenoid as they appear to be very reliable (cant recall one post in 5 years on this Forum).

Faults are generally split/cracked hoses, turbo actuator or EGR.

View attachment 15682
View attachment 15690
[attachment=15698:N21-10151 Golf 5 1.9TDI Vacuum Schematic.png
1 - Solenoid valve block 2 - Non-return valve q Note installation position. 3 - To brake servo
4 - Connecting pipe air filter/turbocharger
5 - Air filter
6 - Intake manifold
7 - Cylinder head/cylinder block 8 - Vacuum reservoir 9 - Bypass flap
q For exhaust gas recirculation cooler.
10 - Radiator
q For exhaust gas recirculation. 11 - Exhaust gas recirculation valve -N18-
12 - Turbocharger
13 - Non-return valve q Note installation position.
 

·
Diesel Geek
Joined
·
4,089 Posts
I've had a couple die on my BKP passat, it caused terrible overboost. Real giveaway is if the car makes a vacuum discharge noise once the engine has stopped.
 

·
Registered
Joined
·
4,574 Posts
If you have a black box with six or so vac lines coming from it you will have the combined n75 boost solenoid and n18 egress one. They suffer from leaks and failure.
I've had a couple die on my BKP passat, it caused terrible overboost. Real giveaway is if the car makes a vacuum discharge noise once the engine has stopped.
You've saved me a post.

I was just going to ask whether you meant hoses or the unit itself failing.

I have an 07 Golf 5 with this combined valve and no problems and I can't recall any posts on the valve failing in 5 years here, plenty on hoses and a few on ancillaries but many boost problems seem t be "sticky vanes" in the VNT
 

·
Registered
Joined
·
9 Posts
Thanks for replys guys

Gerrywac, I put code reader on (autel AL519) and it brought up 2 faults idiot I am erased the codes and never realised it erases

all info, anyway one fault said cracked/faulty turbo ? and the other said faulty boost solenoid or summot like that, I tried to do test again

so I could double check, the car goes into limp mode, there is an air leak somewhere on turbo but I aint got a clue where to start if

I'm honest, this Haynes manual is mind boggling.. it says don't confuse the egr vacuum for the boost solenoid blah blah...I can see the vacuum

solenoid with 6 pipes on it but bloody manual say that ??

p.s

I don't know crap about these code readers etc, just baught it to save a bit of time, I haven't the foggiest idea with turbos

I'd like to think I'm pretty decent around motors but always new territory to explore.
 

·
Registered
Joined
·
4,574 Posts
Thanks for replys guys

Padawan I put code reader on (autel AL519) and it brought up 2 faults idiot I am erased the codes and never realised it erases

all info, anyway one fault said cracked/faulty turbo ? and the other said faulty boost solenoid or summot like that, I tried to do test again

so I could double check, the car goes into limp mode, there is an air leak somewhere on turbo but I aint got a clue where to start if

I'm honest, this Haynes manual is mind boggling.. it says don't confuse the egr vacuum for the boost solenoid blah blah...I can see the vacuum

solenoid with 6 pipes on it but bloody manual say that ??
Can't really comment on the Autel as I use VCDS/Vagcom. With that you have to tell it to erase old codes otherwise it keeps them in memory. Personally I always erase as old codes can cloud the issue

You should be able to clear the codes and rescan.

The code numbers would be very help full as there are many things that can cause limp mode. I don't think a leak would cause limp mode (it would raise an underboost code) one of the most common is overboost (often "sticky vanes" on the turbo) that would raise a code and go into limp mode to protect the engine

I haven't used Haynes manuals for a long time but from what I remember they often cover several models of the car in each manual.

That's why I got the VW factory manual as you can enter the engine, gearbox and model details to get the relevant info
 

·
Registered
Joined
·
9 Posts
Discussion Starter · #8 ·
Ye I tried the rescan but now it says 0 codes, I'll try again tomorrow...never thought about vw manual, can you get them online

or are they for workshops only ?
 

·
Registered
Joined
·
4,574 Posts
Ye I tried the rescan but now it says 0 codes, I'll try again tomorrow...never thought about vw manual, can you get them online
or are they for workshops only ?
Sent from my GT-S7500 using Tapatalk 2

Sometimes faults reset when you turn the key off and on again and warning light will only come on again if the fault still exists.

Drive it and see if it goes into limp and then rescan

Elsawin VW Manual is meant to be subscriprion only but there are "cracked" copies on Ebay from £10 or so
 

·
Registered
Joined
·
9 Posts
Discussion Starter · #11 ·
hi again guys, been waiting for engine light to come back on and son to be home before could get code reader on again...

these are the codes... P0299 ( turbocharge/supercharge underboost ) & ..... P0401 ( Exhaust Gas Recurculation Flow insufficient Detected )

any clues where to start and what to check/do tried using that Elsawin but no joy
 

·
Registered
Joined
·
1 Posts
Hi all

My son has got a Golf 1.9 tdi mk5 (BKC) engine, now hes been having trouble with limp mode, anyway the fault

lies to the turbo boost solenoid, can anyone tell me the location of this solenoid on the engine, according to Haynes manual

its at the left of bulk head ? only solenoid I see there is the egr vacuum solenoid, the manual says not to confuse this with boost solenoid

but I cannot see this anywhere , further reading mention engines with particulate filter and non particulate filter... can anyone help me

with this issue ... am I wrong thinking that the egr vacuum solenoid which has 6 tubes leading to it could also be the boost solenoid combined ?

all advise/help much appreciated
The solenoid valve pressure boost foris connecting with the turbo
 
1 - 12 of 12 Posts
Top