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Old 01-09-10, 14:30   #1
HOW TO - Check your intake manifold pressure sender (G71) using Vagcom/VCDS
RaCiNg SnAkE RaCiNg SnAkE is offline 01-09-10, 14:30

Please note that this guide is for a 4 pin sensor, even though the fitting location diagram for the ACV engine shows a 2 pin intercooler (location is the same though).

The 2 pin sensor is actually just a temperature sensor. The boost pressure is measured by a pipe plumbed directly to the ECU.

TERMINOLOGY


Intake manifold pressure sender / G71 sensor / MAP sensor - they're all the same thing.

FITTING LOCATIONS

Depending on which engine you have will determine the fitting location of your sensor.

If you have an ACV engine, the sensor will be located here:




If you have an AJT engine, the sensor will be located here:




If you have an AHY, AXG or AXL engine, the sensor will be located here:



HOW TO TEST

With the engine not running, but the ignition switched on:

Connect up Vagcom/VCDS
Select the engine control module [01]
Select measured blocks [08]
Select Group 10

You should now be confronted with a screen similar to that below:



The 4 sets of figures are as follows:

1 = The amount of air being drawn into the engine. This will either be 0 or 1275 depending on the version of Vagcom/VCDS.
2 = Atmospheric pressure in millibars
3 = Intake manifold pressure in millibars
4 = This is your throttle pedal position, so should read 0 with your foot off the pedal, and 100 with your foot flat to the floor.

The values shown in 2 and 3 should be nice and stable. Value 3 should be the same as 2 (tolerance 30 mbar).

If everything looks good, then chances are your intake pressure sender is healthy.

If value 3 is fluctuating badly, then you need to double check the connections to the intake pressure sender, or replace it.

As a further test, you can do the following:

Start the engine
Connect up Vagcom/VCDS
Select the engine control module [01]
Select measured blocks [08]
Select Group 10

With the engine idling, disconnect the intake manifold pressure sender connector and watch value 3. It must fall briefly to about 400 mbar and then rise to the same value as value 2.

If it doesn’t, check the connections to the intake pressure sender, or replace it.
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Last edited by RaCiNg SnAkE; 06-09-13 at 18:23.. Reason: Added a quick intro that this guide is for a 4 pin sensor
RaCiNg SnAkE
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Re: How to check your intake manifold pressure sender (G71) using Vagcom/VCDS
23-09-10, 05:16 #2
Editor
Van Jedi

why would I need to do this please? I do seem to have a boost issue at the lower end of the effective turbo rev range.
 
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Re: How to check your intake manifold pressure sender (G71) using Vagcom/VCDS
29-09-10, 10:51 #3
RaCiNg SnAkE
T4 Tinkerer
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The ECU uses information from a variety of sensors to control both the timing of the fuel injection, and the quantity of fuel injected. If any of these sensors aren't working properly, it can cause poor running issues.

It's just something relatively easy to check (if you have vagcom) and rule out really.
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Re: How to check your intake manifold pressure sender (G71) using Vagcom/VCDS
29-09-10, 17:29 #4
Editor
Van Jedi

thank you very much!
 
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Re: HOW TO - Check your intake manifold pressure sender (G71) using Vagcom/VCDS
24-10-10, 07:53 #5
simon6374
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This is a great 'How To' I was going to do MAP sensor next but you beat me to it RS! .
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Re: HOW TO - Check your intake manifold pressure sender (G71) using Vagcom/VCDS
26-10-10, 20:41 #6
RaCiNg SnAkE
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Quote:
Originally Posted by simon6374 View Post
This is a great 'How To' I was going to do MAP sensor next but you beat me to it RS! .
Thank you kind sir! I've been meaning to write it up for a while, and got inspired by your guides to finally spend some time doing it.
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Re: HOW TO - Check your intake manifold pressure sender (G71) using Vagcom/VCDS
19-10-11, 20:19 #7
peterheath1
Van Rookie

Hi

Do you have a list showing what the other 1 to 19 sensors are in the diagram?

My van ran fine one day and wouldn't start the next. it fires but wont pick up, went into safe mode, fuel to the injectors,changed fuel filter, also run a independent fuel supply.The glow plug light goes out within a second.
Any Ideas?

Fault codes
17569 Manifold temp sensor
17946 Charge pressure control
17564 Map sensor
17970 Quantity Adjuster (N146): Upper Limit Reached

It's a 2001 2.5 TDI ACV

Cheers,
Pete.
 
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Re: HOW TO - Check your intake manifold pressure sender (G71) using Vagcom/VCDS
10-11-11, 11:11 #8
Tonibe63
Van Guru

I've got a VAGCOM fault code 17564 which is the MAP sensor.
If you search for MAP sensor on Ebay you will not find one listed for the AJT engine because VW call this sensor the Air Temperature Sensor.


The Bosch number on mine is 028 906 081 which the main dealer confirms is listed as an Air Temperature Sensor on their system.
With a bit of research I've found that it is the same as many VW Air Temperature sensors and specifically this item http://www.ebay.co.uk/itm/3004568975...ht_1075wt_1185

Note:- I am not at all connected with the seller and only posted this up as an example to help resolve any confusion between the terminology.
 
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Re: HOW TO - Check your intake manifold pressure sender (G71) using Vagcom/VCDS
03-09-12, 18:37 #9
bigyeti
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Quote:
Originally Posted by Tonibe63 View Post
I've got a VAGCOM fault code 17564 which is the MAP sensor.
If you search for MAP sensor on Ebay you will not find one listed for the AJT engine because VW call this sensor the Air Temperature Sensor.


The Bosch number on mine is 028 906 081 which the main dealer confirms is listed as an Air Temperature Sensor on their system.
With a bit of research I've found that it is the same as many VW Air Temperature sensors and specifically this item http://www.ebay.co.uk/itm/3004568975...ht_1075wt_1185

Note:- I am not at all connected with the seller and only posted this up as an example to help resolve any confusion between the terminology.
To Clarify

028 906 081 temperature sensor / F >> 70-X-250 000*/ AJT,AHY
The early ones which also have a vac pipe located near to this temperature sensor, the vac pipe runs to MAP sensor which is inside the ECU housing.

038 906 051 thrust sensor / F 70-X-250 001>>*70-1-200 000/ AJT,AHY,AXG
038 906 051B thrust sensor / F 70-1-200 001>>*/ AJT,AHY,AXG, AYY

The later ones which have the MAP sensor (called thrust sensor in vagcat) in the locations indicated in the how too and no vac pipe to ECU
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