test N75 > VCDS > Measuring Blocks > Switch to basic Settings > "Greyed Out"

Ghastly

Veteran Member
Joined
Sep 13, 2008
Location
mom's basement
TDI
2004 Jetta Sedan, 2009 Jetta Wagon
test N75 > VCDS > Measuring Blocks > Switch to basic Settings > "Greyed Out"

I want to test turbo actuator function by getting VCDS cycle the N75 valve. I *think* I need to go here:

Select Control Module > 01-Engine > Measuring Blocks > Switch to basic Settings

But "Switch to basic Settings" is greyed out, and clicking on it does nothing. I've also entered the 011 group before trying to click "Switch to basic Settings" button.

I have a 2004 PD BEW, and a legal Ross Tech cable with KII-USB Interface.

What am I doing wrong?
 

Ghastly

Veteran Member
Joined
Sep 13, 2008
Location
mom's basement
TDI
2004 Jetta Sedan, 2009 Jetta Wagon
The ECU in my car only allows sequential output tests, which scares me a bit because I don't know what to expect. If I had some info on what to expect, I'd do it. I have a Bentley Manual, which should tell me what to expect, but I can't find anything in that piece of junk.

According to info here on tdiClub, when in the 011 group "Basic Settings" under "Measuring Blocks" is supposed to perform one output test ~ cycle the N75 valve.
 

jef@rosstech

Associate Ross-Tech Vendor , w/Business number
Joined
Jul 19, 2010
Location
knoxville
TDI
2004 Dog hauling, wood towing, pinball stashing Jetta wagon
Start the engine and let it run for a few seconds, then shut engine off. Turn ignition back on but do not start engine. With VCDS, start your scan of the ECM. Click on the [Output Test - 03] button.

There is nothing to fear, if a test is not the one you want, skip to the next one until you get to the N75.

Now then, few things to keep in mind:


  • Each test plan last about 1 minute
  • Each time you skip to the next test plan, that 1 minute time resets
  • If you use up the 1 minute on a given plan, or go though to the end of the output test plan, you must exit the ECM and restart the engine for a few seconds before you can do an output test again.
Before you even take anything apart, just give it a try and listed under the hook, you will hear some things clicking, everyone should try it out just to get an idea of what the output test function does. Keep in mind that what it does will vary depending on the control module you are working with.

You can even do an output test on your instrument cluster, give it a whirl and see what happens (it is safe to do).
 

Uwe

Vendor , w/Business number
Joined
Feb 24, 2000
Location
Lansdale, PA, USA
To answer the original question, the BEW engine uses KWP-2000. Unlike the older KW-1281 protocol, used on the ALHs, KWP-2000 does not allow for a simple flip between Measuring Blocks and Basic Settings. So if you want to go to a particular Basic Settings group, you must exit Measuring Blocks, then click the Basic Settings button and go to the group you want. FWIW, it's the same with the dealers' tools as well.

-Uwe-
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
And the basic settings test is a much better test of the turbo operation. The N75 gets cycled with either the output test or the basic settings test.

The basic settings test is done with the engine operating, it will go to 1400 rpm, then cycle the turbo controls. With this test you can expect to see about 1130 mbar turbo output, and you can easily hear the exhaust note change as the exhaust gets more restrictive.
 

klitoni

banned
Joined
Nov 17, 2010
Location
Tirana, Albania
TDI
Passat 3BG 130 hp PD
And the basic settings test is a much better test of the turbo operation. The N75 gets cycled with either the output test or the basic settings test.

The basic settings test is done with the engine operating, it will go to 1400 rpm, then cycle the turbo controls. With this test you can expect to see about 1130 mbar turbo output, and you can easily hear the exhaust note change as the exhaust gets more restrictive.
Please can you explain this to me?How to do that ?engine basic settings group 11? engine running in idle?how to understand if n75 and vnt works?seeing the vnt stick?how long the test last?what should i do then?
thanks man
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Engine running at idle.
Select the ENGINE Controller
Choose BASIC SETTINGS -04,
Choose GROUP 011 (or turbo controls from the pull-down menu)
Choose GRAPH if you want, or just watch the numbers.
The N75 duty cycle will cycle from OFF to ON every 5 seconds or so. (about 10% duty cycle to about 90% duty cycle.)
The MAP actual pressure should cycle at least 30 mbar with a stock turbo if the test is done at idle - as the ALH engines do. (less change will probably occur with a larger than stock turbo.) If the engine accelerates to 1400 rpm (as the PD engines do that I am familiar with) then the MAP should change by at least 80 mbar. I would say that most PD engines with stock turbos change about 150 mbar from min boost to max boost at 1400 rpm.
The turbo vane actuator should cycle up and down about 11-14 mm (depends upon turbo - others may have different travel) and it should pull up firmly onto the full travel stop set screw.
You can hear a definite sound change in the exhaust - very noticeable.
If you hook up a vacuum gauge to the N75 output to the vane actuator it should change from about 2" hg vacuum (or less) to about 20" hg vacuum (or more).

So with this test you can check whatever you need on this control loop for basic troubleshooting.
 
Last edited:

klitoni

banned
Joined
Nov 17, 2010
Location
Tirana, Albania
TDI
Passat 3BG 130 hp PD
Engine running at idle.
Select the ENGINE Controller
Choose BASIC SETTINGS -04,
Choose GROUP 011 (or turbo controls from the pull-down menu)
Choose GRAPH if you want, or just watch the numbers.
The N75 duty cycle will cycle from OFF to ON every 5 seconds or so. (about 10% duty cycle to about 90% duty cycle.)
The MAP actual pressure should cycle at least 30 mbar with a stock turbo if the test is done at idle - as the ALH engines do. (less change will probably occur with a larger than stock turbo.) If the engine accelerates to 1400 rpm (as the PD engines do that I am familiar with) then the MAP should change by at least 80 mbar. I would say that most PD engines with stock turbos change about 150 mbar from min boost to max boost at 1400 rpm.
The turbo vane actuator should cycle up and down about 11-14 mbar (depends upon turbo - others may have different travel) and it should pull up firmly onto the full travel stop set screw.
You can hear a definite sound change in the exhaust - very noticeable.
If you hook up a vacuum gauge to the N75 output to the vane actuator it should change from about 2" hg vacuum (or less) to about 20" hg vacuum (or more).

So with this test you can check whatever you need on this control loop for basic troubleshooting.
First thanks for the reply :)
The map pressure it shows on screen after i go to group 11 ?Yes i have a pd engine avf 130 cv.if i see the vnt stick moving by n75 it means that is all fine.How can i stop the test?
Sorry for losing your time
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Yes, the MAP pressure will be displayed.
For most PD engines you have to select a button at the top that says "ON-OFF-NEXT" to start the test. You stop it by selecting that button again, or by just selecting "Done - Close" on the bottom of the screen.

I think it will be self explanatory once you go Basic Settings- 04 and then group 011.
 

klitoni

banned
Joined
Nov 17, 2010
Location
Tirana, Albania
TDI
Passat 3BG 130 hp PD
Yes, the MAP pressure will be displayed.
For most PD engines you have to select a button at the top that says "ON-OFF-NEXT" to start the test. You stop it by selecting that button again, or by just selecting "Done - Close" on the bottom of the screen.

I think it will be self explanatory once you go Basic Settings- 04 and then group 011.
Thanks man all clear now thanx to you.Ill do a video of the vnt stick and ill check the iniectors too.
The MAF can i check on idle? cus i dont have a driver license and my bro is not home? ;)
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Yes the MAF test is BASIC SETTINGS-04, then choose group 003. It will raise the idle (on most PDs) to 1400 rpm and vary the EGR. You should see the MAF reading go from about 470 to about 230 as it shifts every 5 seconds or so.

You do not have to drive for either test.
 

klitoni

banned
Joined
Nov 17, 2010
Location
Tirana, Albania
TDI
Passat 3BG 130 hp PD
Yes the MAF test is BASIC SETTINGS-04, then choose group 003. It will raise the idle (on most PDs) to 1400 rpm and vary the EGR. You should see the MAF reading go from about 470 to about 230 as it shifts every 5 seconds or so.

You do not have to drive for either test.
Wow basic settings are much nicer than measuring blocks in "safe functions" ;)
Thanks man ill keep in touch for another answers lol
 
Last edited:

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Both Basic Settings and Output tests are generally pretty safe to do on the TDI's in the ENGINE controller. Both can be helpful in troubleshooting issues.

But some of the Basic Settings features on some controllers are sometimes used for the ECU to re-learn operating parameters, and can cause changes in operation.

The measuring blocks are extremely valuable for diagnostics, but do not have the WOW factor of some of the Basic Settings tests.
 

klitoni

banned
Joined
Nov 17, 2010
Location
Tirana, Albania
TDI
Passat 3BG 130 hp PD
Both Basic Settings and Output tests are generally pretty safe to do on the TDI's in the ENGINE controller. Both can be helpful in troubleshooting issues.

But some of the Basic Settings features on some controllers are sometimes used for the ECU to re-learn operating parameters, and can cause changes in operation.

The measuring blocks are extremely valuable for diagnostics, but do not have the WOW factor of some of the Basic Settings tests.
I understand it.thanks and you look a pro on using vcds ;)Congrats
 

masondupre

Active member
Joined
Jan 20, 2012
Location
SC
TDI
2003 Jetta auto TDI, Malone Stage 1, Dynamic EGR; 2008 Grand Cherokee CRD, GDE EcoTune, DPF delete;2012 Touareg, stock
Engine running at idle.
Select the ENGINE Controller
Choose BASIC SETTINGS -04,
Choose GROUP 011 (or turbo controls from the pull-down menu)
Choose GRAPH if you want, or just watch the numbers.
The N75 duty cycle will cycle from OFF to ON every 5 seconds or so. (about 10% duty cycle to about 90% duty cycle.)
The MAP actual pressure should cycle at least 30 mbar with a stock turbo if the test is done at idle - as the ALH engines do. (less change will probably occur with a larger than stock turbo.) If the engine accelerates to 1400 rpm (as the PD engines do that I am familiar with) then the MAP should change by at least 80 mbar. I would say that most PD engines with stock turbos change about 150 mbar from min boost to max boost at 1400 rpm.
The turbo vane actuator should cycle up and down about 11-14 mbar (depends upon turbo - others may have different travel) and it should pull up firmly onto the full travel stop set screw.
You can hear a definite sound change in the exhaust - very noticeable.
If you hook up a vacuum gauge to the N75 output to the vane actuator it should change from about 2" hg vacuum (or less) to about 20" hg vacuum (or more).

So with this test you can check whatever you need on this control loop for basic troubleshooting.
Thanks Dan! Just used this procedure to check out my 2003 Jetta TDI. Other than a little bit of a squeak as the turbo actuator linkage moves she appears to fine.
 

kraftwerkturbo

Veteran Member
Joined
Sep 21, 2014
Location
Brighton, MI
TDI
2005 Golf 1.9 TDI auto
Tried to log the basis settings test: 003
Sunday 1 March 2015 15:26:01:36008-VCID:275D430D9561BC190FA-5124 VCDS Version: Release 14.10.1 (x64) Data version: 20150130
038 997 016 L R4 1.9L EDC G000AG 3791

Group A: '003 Group B:
Engine Speed Exhaust Gas Exhaust Gas Exhaust Gas
TIME (G28) Recirculat. (spec.) Recirculat. (actual) Recirc. Duty Cycle TIME
Marker STAMP /min mg/str % STAMP
0.08 1008 EGR On 185 50.1
0.24 1008 EGR On 190 50.1
0.39 1008 EGR On 185 50.1
0.55 1029 EGR On 180 50.1
0.7 1008 EGR On 185 50.1
0.86 1029 EGR On 190 50.1
1.02 1029 EGR On 190 50.1
1.17 1071 EGR On 180 50.1
1.33 1071 EGR On 175 50.1
1.48 1071 EGR On 175 50.1
1.64 1092 EGR On 180 50.1
1.8 1113 EGR On 190 50.1
1.95 1113 EGR On 175 50.1
2.11 1113 EGR On 190 50.1
2.26 1113 EGR On 190 50.1
2.42 1155 EGR On 185 50.1
2.58 1155 EGR On 180 50.1
2.73 1155 EGR On 185 50.1
2.89 1155 EGR On 185 50.1
3.05 1176 EGR On 180 50.1
3.2 1176 EGR On 180 50.1
3.36 1197 EGR On 185 50.1
3.51 1197 EGR On 180 50.1
3.67 1197 EGR On 180 50.1
3.82 1218 EGR On 175 50.1
3.98 1218 EGR On 175 50.1
4.14 1218 EGR On 180 50.1
4.29 1260 EGR On 175 50.1
4.45 1239 EGR On 175 50.1
4.6 1239 EGR On 175 50.1
4.76 1239 EGR On 185 50.1
4.92 1260 EGR On 185 50.1
5.07 1260 EGR On 185 50.1
5.23 1260 EGR On 170 50.1
5.38 1281 EGR On 205 50.1
5.54 1260 EGR On 195 50.1
5.7 1239 EGR On 175 50.1
5.85 1302 EGR On 165 50.1
6.01 1323 EGR On 150 50.1
6.16 1176 EGR On 225 50.1
6.31 1365 EGR On 130 50.1
6.47 1134 EGR On 245 50.1
6.62 1365 EGR On 125 50.1
6.76 1155 EGR On 240 50.1
6.92 1302 EGR On 165 50.1
7.08 1239 EGR On 195 50.1
7.23 1260 EGR On 235 50.1
7.39 1365 EGR On 120 50.1
7.54 1218 EGR On 260 50.1
7.69 1428 EGR On 110 50.1
7.86 1176 EGR Off 250 95.5
8.03 1554 EGR Off 335 95.5
8.18 1890 18.7 395 100.6
 

kraftwerkturbo

Veteran Member
Joined
Sep 21, 2014
Location
Brighton, MI
TDI
2005 Golf 1.9 TDI auto
Group 011:

Sunday 1 March 2015 15:25:00:36008-VCID:275D430D9561BC190FA-5124 VCDS Version: Release 14.10.1 (x64) Data version: 20150130
038 997 016 L R4 1.9L EDC G000AG 3791

Group A: '011 Group B:
Engine Speed Charge Pressure Boost Pressure Charge Pressure
TIME (G28) Control Status (actual) Control Duty Cycle TIME
Marker STAMP /min mbar % STAMP
0.11 1029 ON 1020 90.3
0.27 1050 ON 1020 90.3
0.43 1050 ON 1020 90.3
0.58 1071 ON 1030.2 90.3
0.74 1092 ON 1030.2 90.3
0.89 1092 ON 1030.2 90.3
1.05 1092 ON 1030.2 90.3
1.2 1113 ON 1030.2 90.3
1.36 1113 ON 1040.4 90.3
1.52 1113 ON 1040.4 90.3
1.67 1113 ON 1040.4 90.3
1.83 1134 ON 1040.4 90.3
1.98 1134 ON 1040.4 90.3
2.14 1134 ON 1040.4 90.3
2.3 1155 ON 1040.4 90.3
2.45 1155 ON 1050.6 90.3
2.61 1155 ON 1050.6 90.3
2.77 1155 ON 1050.6 90.3
2.92 1176 ON 1050.6 90.3
3.08 1176 ON 1050.6 90.3
3.23 1176 ON 1050.6 90.3
3.39 1197 ON 1050.6 90.3
3.55 1197 ON 1060.8 90.3
3.7 1197 ON 1060.8 90.3
3.86 1218 ON 1060.8 90.3
4.01 1239 ON 1060.8 90.3
4.17 1239 ON 1060.8 90.3
4.33 1260 ON 1071 90.3
4.48 1260 ON 1071 90.3
4.64 1281 ON 1071 90.3
4.79 1281 ON 1071 90.3
4.95 1281 ON 1081.2 90.3
5.11 1302 ON 1081.2 90.3
5.27 1302 ON 1081.2 90.3
5.42 1302 ON 1081.2 90.3
5.58 1302 ON 1081.2 90.3
5.73 1323 ON 1081.2 90.3
5.89 1323 ON 1091.4 90.3
6.05 1344 ON 1091.4 90.3
6.2 1344 ON 1091.4 90.3
6.36 1344 ON 1091.4 90.3
6.51 1344 ON 1091.4 90.3
6.67 1365 ON 1091.4 90.3
6.83 1365 ON 1101.6 90.3
6.98 1386 ON 1101.6 90.3
7.14 1386 ON 1101.6 90.3
7.3 1407 ON 1101.6 90.3
7.45 1407 OFF 1111.8 9.9
7.61 1386 OFF 1111.8 9.9
7.76 1386 OFF 1111.8 9.9
7.92 1407 OFF 1111.8 9.9
8.07 1407 OFF 1111.8 9.9
8.23 1386 OFF 1111.8 9.9
8.39 1407 OFF 1111.8 9.9
8.54 1407 OFF 1111.8 9.9
8.7 1407 OFF 1122 9.9
8.85 1407 OFF 1122 9.9
9.01 1407 OFF 1122 9.9
9.17 1407 OFF 1122 9.9
9.32 1407 OFF 1122 9.9
9.48 1407 OFF 1122 9.9
9.63 1407 OFF 1122 9.9
9.79 1407 OFF 1122 9.9
9.95 1407 OFF 1122 9.9
10.1 1407 OFF 1122 9.9
10.26 1407 OFF 1122 9.9
10.41 1407 OFF 1122 9.9
10.57 1407 OFF 1122 9.9
10.73 1407 OFF 1122 9.9
10.88 1407 OFF 1122 9.9
11.04 1407 OFF 1122 9.9
11.19 1407 OFF 1122 9.9
11.35 1407 OFF 1122 9.9
11.51 1407 OFF 1122 9.9
11.66 1407 OFF 1122 9.9
11.82 1407 OFF 1122 9.9
11.97 1407 OFF 1122 9.9
12.13 1407 OFF 1122 9.9
12.29 1407 OFF 1122 9.9
12.44 1407 OFF 1122 9.9
12.6 1407 OFF 1122 9.9
12.76 1407 OFF 1122 9.9
12.92 1407 OFF 1122 9.9
13.07 1407 OFF 1122 9.9
13.23 1407 OFF 1122 9.9
13.38 1407 OFF 1122 9.9
13.54 1386 OFF 1122 9.9
13.69 1407 OFF 1122 9.9
13.85 1407 OFF 1122 9.9
14.01 1407 OFF 1122 9.9
14.16 1407 OFF 1122 9.9
14.32 1407 OFF 1122 9.9
14.47 1407 OFF 1122 9.9
14.63 1407 OFF 1122 9.9
14.79 1407 OFF 1122 9.9
14.94 1407 OFF 1122 9.9
15.1 1407 OFF 1122 9.9
15.26 1407 OFF 1122 9.9
15.41 1407 OFF 1122 9.9
15.57 1407 OFF 1122 9.9
15.72 1407 OFF 1122 9.9
15.88 1407 OFF 1122 9.9
16.04 1407 OFF 1122 9.9
16.19 1407 OFF 1122 9.9
16.35 1407 OFF 1122 9.9
16.5 1407 OFF 1122 9.9
16.66 1407 OFF 1122 9.9
16.81 1386 OFF 1122 9.9
16.97 1407 OFF 1122 9.9
17.13 1407 OFF 1122 9.9
17.28 1407 OFF 1122 9.9
17.44 1407 ON 1122 90.3
17.59 1407 ON 1122 90.3
17.75 1407 ON 1122 90.3
17.91 1407 ON 1122 90.3
18.06 1407 ON 1122 90.3
18.22 1407 ON 1122 90.3
18.38 1407 ON 1122 90.3
18.53 1407 ON 1122 90.3
18.69 1407 ON 1122 90.3
18.83 1407 ON 1122 90.3
18.99 1407 ON 1122 90.3
19.14 1386 ON 1122 90.3
19.3 1407 ON 1122 90.3
19.46 1407 ON 1122 90.3
19.63 1407 ON 1122 90.3
19.8 1407 ON 1122 90.3
19.96 1407 ON 1122 90.3
20.12 1407 ON 1122 90.3
20.27 1386 ON 1122 90.3
20.43 1407 ON 1122 90.3
20.58 1407 ON 1122 90.3
20.74 1407 ON 1122 90.3
20.9 1407 ON 1122 90.3
21.05 1407 ON 1122 90.3
21.21 1386 ON 1122 90.3
21.36 1407 ON 1122 90.3
21.52 1407 ON 1122 90.3
21.68 1407 ON 1122 90.3
21.83 1407 ON 1122 90.3
21.99 1407 ON 1122 90.3
22.15 1407 ON 1122 90.3
22.3 1386 ON 1122 90.3
 

kraftwerkturbo

Veteran Member
Joined
Sep 21, 2014
Location
Brighton, MI
TDI
2005 Golf 1.9 TDI auto
When running the n75 output test, boost does NOT change when duty cycle changes, stays up. Also split the line going to the actuator and put vac gauge in: vac stays up all the time.

Maybe N75 hoses connected wrongly? I have all 3 nipples on one side.
Top (closest to electrical connector): short vent hose
middle: going down to turbo actuator
bottom: goes to a T that also goes to vac canister
 

tongsli

Top Post Dawg
Joined
Jan 31, 2000
Location
Baltimore, MD
TDI
2000 Jetta TDI, 2004, Jetta Wagon TDI PD
Thanks Dan

Engine running at idle.
Select the ENGINE Controller
Choose BASIC SETTINGS -04,
Choose GROUP 011 (or turbo controls from the pull-down menu)
Choose GRAPH if you want, or just watch the numbers.
The N75 duty cycle will cycle from OFF to ON every 5 seconds or so. (about 10% duty cycle to about 90% duty cycle.)
The MAP actual pressure should cycle at least 30 mbar with a stock turbo if the test is done at idle - as the ALH engines do. (less change will probably occur with a larger than stock turbo.) If the engine accelerates to 1400 rpm (as the PD engines do that I am familiar with) then the MAP should change by at least 80 mbar. I would say that most PD engines with stock turbos change about 150 mbar from min boost to max boost at 1400 rpm.
The turbo vane actuator should cycle up and down about 11-14 mbar (depends upon turbo - others may have different travel) and it should pull up firmly onto the full travel stop set screw.
You can hear a definite sound change in the exhaust - very noticeable.
If you hook up a vacuum gauge to the N75 output to the vane actuator it should change from about 2" hg vacuum (or less) to about 20" hg vacuum (or more).

So with this test you can check whatever you need on this control loop for basic troubleshooting.
Thanks for posting this info
 

touaregv10tdi

Veteran Member
Joined
Jan 29, 2006
Location
Fort Lauderdale - Florida
TDI
2013 Beetle TDi,2000 Beetle TDi, 2016 BMW X5 Diesel, 2004 Touareg V10 TDi,2015 Beetle TDi, 2005 Jetta TDi
Boost issue

2005 Jetta TDi PD (BEW)
I am having some boost issues. When I ran the VCDS I get the following:
1 Fault Found:
16683 - Boost Pressure Regulation P0299 - 000 - Control Range Not Reached
I have checked the entire vacuum hoses. None are bad.
I have also replaced the O rings in the intercooler and all hoses, pipings.
My CEL comes on, I followed the instructions above but they are kind of vague to me.
I am out of options on this issue. I have replaced the N75 with an used one. Also replaced the MAF with a used one. (bought both from the yard for $20)
Can someone shine a light on this issue ?

 

Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
2005 Jetta TDi PD (BEW)
I am having some boost issues. When I ran the VCDS I get the following:
1 Fault Found:
16683 - Boost Pressure Regulation P0299 - 000 - Control Range Not Reached
I have checked the entire vacuum hoses. None are bad.
I have also replaced the O rings in the intercooler and all hoses, pipings.
My CEL comes on, I followed the instructions above but they are kind of vague to me.
I am out of options on this issue. I have replaced the N75 with an used one. Also replaced the MAF with a used one. (bought both from the yard for $20)
Can someone shine a light on this issue ?

When you're in basic setting 011 and you press the "On/Off/Next" button, the engine RPMs come up to about 1400 and the N75 will cycle between full vacuum and no vacuum every 5-10 seconds or so.


When it's doing this, either use a mirror to look behind the engine or get underneath the car and watch the turbo actuator. Verify if it's getting the VNT arm pulled all the way down to the stop screw or not when the computer tells the N75 to switch full vacuum to the turbo.

If it does NOT pull all the way down to the stop, we need to figure out why. You will need a vacuum pump with gauge to further diagnose. First things, put the vacuum pump to the turbo actuator directly and measure how much vacuum it takes to pull the actuator to the stop. It should be about 18" mg. If it moves very little and leaks back down quickly, you have a bad actuator.

If it does move all the way to the stop at about 18" of mg and it doesn't leak vacuum, the actuator is fine and correctly adjusted. Move on to checking vacuum.

Run basic setting 11 again, this time measure how much vacuum the hose you just removed from the turbo actuator is getting. It should cycle from at least 25" mg to zero every few seconds. If it can't get more than a max of 20" of mg, there's a leak somewhere and it is absolutely affecting boost control.

I generally start by removing the small hose that goes to the large vacuum pipe going to the brake booster. That small hose feeds the vacuum to the n75 and the various other vacuum changeover valves the BEW has (one for intake manifold runner flaps, another for EGR cooler flap...). Put your hand vacuum pump with gauge onto the nipple that you just removed the hose from. You're now measuring how much vacuum is coming out of the vacuum pump/tandem pump directly.

On the BEW, I've had that black plastic pipe crack on the underside of one of the 90 degree bends it has and create a big vacuum leak. I've also seen a few tandem pumps where that large nipple that the vacuum pipe connects to is worn or loose and is creating a vacuum leak...
 

JoshWagen

Veteran Member
Joined
May 2, 2015
Location
Kansas City
TDI
Current: '15 GSW, '11 A3 Former: '13 JSW, 99.5 Jetta
When you're in basic setting 011 and you press the "On/Off/Next" button, the engine RPMs come up to about 1400 and the N75 will cycle between full vacuum and no vacuum every 5-10 seconds or so.
When it's doing this, either use a mirror to look behind the engine or get underneath the car and watch the turbo actuator. Verify if it's getting the VNT arm pulled all the way down to the stop screw or not when the computer tells the N75 to switch full vacuum to the turbo.
If it does NOT pull all the way down to the stop, we need to figure out why. You will need a vacuum pump with gauge to further diagnose. First things, put the vacuum pump to the turbo actuator directly and measure how much vacuum it takes to pull the actuator to the stop. It should be about 18" mg. If it moves very little and leaks back down quickly, you have a bad actuator.
If it does move all the way to the stop at about 18" of mg and it doesn't leak vacuum, the actuator is fine and correctly adjusted. Move on to checking vacuum.
Run basic setting 11 again, this time measure how much vacuum the hose you just removed from the turbo actuator is getting. It should cycle from at least 25" mg to zero every few seconds. If it can't get more than a max of 20" of mg, there's a leak somewhere and it is absolutely affecting boost control.
I generally start by removing the small hose that goes to the large vacuum pipe going to the brake booster. That small hose feeds the vacuum to the n75 and the various other vacuum changeover valves the BEW has (one for intake manifold runner flaps, another for EGR cooler flap...). Put your hand vacuum pump with gauge onto the nipple that you just removed the hose from. You're now measuring how much vacuum is coming out of the vacuum pump/tandem pump directly.
On the BEW, I've had that black plastic pipe crack on the underside of one of the 90 degree bends it has and create a big vacuum leak. I've also seen a few tandem pumps where that large nipple that the vacuum pipe connects to is worn or loose and is creating a vacuum leak...
Thanks a lot for this walk through. Really helped me troubleshoot my low power issue. My VNT looks like it's operating well and holding vacuum.
 

Saphauler

Active member
Joined
Apr 16, 2015
Location
NH
TDI
2005 Jetta BEW 5-speed, 2011 Sportwagen 6-speed
I'm trying to diagnose a low power/low turbo issue on an '05 BEW. I found this thread and ran the N75 test, and I think it passed the test...cycled between 90.3% and 9.9%...are those the correct values? Log report in the link below.

I also wanted to test the MAF, and reading this thread, I thought I was supposed to us Group 003, but it came back invalid or something. Is there a different number for this?

Thanks for the help.

N75 Test Log
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
I'm trying to diagnose a low power/low turbo issue on an '05 BEW. I found this thread and ran the N75 test, and I think it passed the test...cycled between 90.3% and 9.9%...are those the correct values? Log report in the link below.
I also wanted to test the MAF, and reading this thread, I thought I was supposed to us Group 003, but it came back invalid or something. Is there a different number for this?
Thanks for the help.
N75 Test Log
Your ECM is sending the right signal, but the pressure does not change - it should cycle up and down with the N75 signal.

So Wonnebeer's comment is right on the money. Does the turbo actuator move?
If it does not move, check your vacuum system.
If it does move full stroke - about half an inch, then you have turbo issues.

Vacuum issues are more common. You should have SYSTEM vacuum of 20" or more at idle to the N75.
You should see the N75 vacuum output go from <3" hg to >18" hg as the signal goes up and down.

Group 3 or EGR test should work for your car in basic settings.
 

Saphauler

Active member
Joined
Apr 16, 2015
Location
NH
TDI
2005 Jetta BEW 5-speed, 2011 Sportwagen 6-speed
I didn't know where the actuator was until yesterday, and I didn't know that's what the N75 does. I will check it out this weekend. Things have been crazy busy, and since the car gets me from Point A to Point B, I've been living with the low power...but really need to get this fixed.

So as the control status cycles on/off, the boost pressure actual should change? Rereading some of the posts above, it looks like I should be seeing a 150mbar change...I missed that on the log.

I remember hearing a noise when it cycled on/off, but couldn't tell what it was coming from.
 
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