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Fuel supply system -> 3.2 Checking fuel system for leaks for Your Volkswagen Touareg SUV First Generation (2002-2010)

lk  
Touareg 2003 ➤  
8-cylinder injection engine - Edition 11.2011  
3.1  
Assembly overview - activated charcoal filter system  
1 - Expansion tank  
2 - Gravity valve  
3 - To gravity valve  
4 - Pressure retention valve  
❑ Function ⇒ page 118 .  
5 - 9 Nm  
6 - Connecting hose  
7 - Air filter  
❑ Clean if soiled.  
8 - Connector  
❑ For breather line.  
9 - Activated charcoal filter  
10 - 9 Nm  
11 - Connector  
12 - Activated charcoal filter  
solenoid valve 1 -N80-  
13 - Rubber bracket  
14 - To connection  
❑ On intake manifold  
15 - Breather line  
Function of pressure retention valve  
From gravity valve (on expansion tank) the pressure retention  
valve is open in both directions of flow. -Arrow 1- is the side to  
expansion tank.  
On the other side it is only open for flow in one direction.  
-Arrow 2- is the side to activated charcoal filter.  
3.2  
Checking fuel system for leaks  
Special tools and workshop equipment required  
118  
Rep. gr.20 - Fuel supply system  
Touareg 2003 ➤  
8-cylinder injection engine - Edition 11.2011  
♦ Hose clips up to 25 mm Ø -3094-  
♦ Tester -V.A.G 1371-  
Procedure:  
– Remove rear right wheel and wheel housing liner.  
– Clamp off hose -arrow- between activated charcoal filter and  
air filter using a hose clamp -3094- .  
– Disconnect breather line -arrow- to solenoid valve in engine  
compartment.  
3. Activated charcoal filter system  
119  
Touareg 2003 ➤  
8-cylinder injection engine - Edition 11.2011  
– Connect tester -V.A.G 1371- to breather line -arrow- as shown  
in illustration.  
– Connect valve adapter of tester -V.A.G 1371- to tyre valve.  
– Regulate the pressure to 35 mbar with valve -A-. When the  
pressure has stabilised, it must not drop below 30 mbar after  
5 minutes.  
If no pressure builds up or the pressure is not held for at least 5  
minutes, localise leak as follows:  
– Perform visual check on all components and hoses of the fuel  
system.  
Note  
Also check fuel tank cap for leaks.  
Only if still no fault has been detected:  
– Check breather line and activated charcoal filter for leaks. To  
do this, disconnect breather line -A- from activated charcoal  
filter and seal connection with a plug -B-.  
– Repeat pressure test.  
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If pressure still drops, the leakage can be found on the activated  
charcoal filter or breather line:  
– When valve is open -A-, check the following lines and compo‐  
nents for leaks by hearing, touching, with commercially avail‐  
able leak detector spray or using ultrasonic tester -V.A.G  
1842- .  
♦ Line from engine compartment to activated charcoal filter.  
♦ Activated charcoal filter  
If the pressure does not drop again, the leakage can be found on  
fuel tank:  
– To do this, reconnect breather line -A- to activated charcoal  
filter.  
120  
Rep. gr.20 - Fuel supply system  
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Touareg 2003 ➤  
8-cylinder injection engine - Edition 11.2011  
– With valve -A- is open, check fuel tank for leaks by hearing,  
touching, with commercially available leak detector spray or  
ultrasonic tester -V.A.G 1842- .  
Caution  
After completing work check tyre pressure!  
3. Activated charcoal filter system  
121