2009 Mk4 City Golf - DTC P0442 Evap System Small Leak

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Rembrant

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Hi Folks,

I am getting repeated P0442 DTC on my 2009 Mk4 City Golf.
Please see below:

Mode 03: Emission related fault codes

Address 7E8: 1 Fault Found:
P0442 - EVAP Emission Control Sys: Small Leak

Thursday,30,April,2015,17:17:33:24871
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 14.10.2.0 (x64)
Data version: 20150311
www.Ross-Tech.com

The full story is that the car was in a fender bender and took a smack in the left rear corner. This DTC showed up soon after that. The body shop that repaired the car said that they found a cracked canister, and that they replaced it. The code didn't come back immediately, but it did come back. I should also note that the car has also become a bit cantankerous to fill with gas...I have to feed her slow now.

Anyway, my questions are: How do I troubleshoot this? What am I looking for, and where? Any suggestions? Am I looking under the car, or inside the quarter panel in the trunk/hatch area? Any advice on where to start would be appreciated. I'm fine with wrenches and/or a multi-meter, but this one is new on me.

Thanks,
Rem

Code:
Thursday,30,April,2015,17:27:53:24871
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 14.10.2.0 (x64)
Data version: 20150311
www.Ross-Tech.com


VIN: 9BWEL41J494016080   License Plate: 
Mileage: 152360km-94672mi   Repair Order: 


Chassis Type: 1J (1J - VW Golf/Bora IV (1998 > 2006))
Scan: 01 02 03 08 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57 75
          76
 
VIN: 9BWEL41J494016080   Mileage: 152360km-94672miles
-------------------------------------------------------------------------------
Address 01: Engine        Labels: None
   Part No SW: 06A 906 012 AB    HW: 06A 906 032 RF
   Component: 2,0L 85KW       G   0802  
   Revision: 00ÿW        Serial number:  000-00000.00.
   Coding: 0000001
   Shop #: WSC 00000 785 00200
   VCID: 5CB7BB279C4AA0C1527-5140

No fault code found.
Readiness: 0110 1101

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 1C0-907-37x-ABS.lbl
   Part No: 1C0 907 379 L
   Component: ABS FRONT MK60      0101  
   Coding: 0004097
   Shop #: WSC 00000 785 00200
   VCID: 3365309B51544FB9A3D-5140

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: 6Q0-909-605-VW5.lbl
   Part No: 1C0 909 601 
   Component: 1L AIRBAG VW51      0011  
   Coding: 12620
   Shop #: WSC 00000  
   VCID: 5DB1B623D050A9C9259-8008

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 1J0-920-xx5-17.lbl
   Part No: 1JE 920 807 
   Component: KOMBI+WEGFAHRSP VDO V01  
   Coding: 11332
   Shop #: WSC 00000  
   VCID: 7AFBDDBF66BE7EF120B-5122
   9BWEL41J494016080     VWZ7Z0H0243276

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway        Labels: 6N0-909-901-19.lbl
   Part No: 6N0 909 901 
   Component: Gateway K<->CAN    0001  
   Coding: 00006
   Shop #: WSC 00000  
   VCID: 70EFFF9730C234A19EF-5106

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv.        Labels: 1C0-959-799.lbl
   Part No: 1C0 959 799 C
   Component: 8C Komfortgerát HLO 0004  
   Coding: 00258
   Shop #: WSC 00000  
   VCID: 377D048B152CA3999F5-4AE8

   Subsystem 1 - Part No: 1C1959801A
   Component: 8C Tõrsteuer.FS KLO 0202  

   Subsystem 2 - Part No: 1C1959802A
   Component: 8C Tõrsteuer.BF KLO 0202  

   Subsystem 3 - Part No: 1C0959811A
   Component: 8C Tõrsteuer.HL KLO 0202  

   Subsystem 4 - Part No: 1C0959812A
   Component: 8C Tõrsteuer.HR KLO 0202  

1 Fault Found:
00912 - Window Regulator Switch; Front Left (E40) 
            27-10 - Implausible Signal - Intermittent

End-------------------------(Elapsed Time: 06:14)--------------------------
 
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Dana

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Well a small evap leak isn't a big deal but if that vehicle won't take fuel (shuts off the pump and/or shoots gas back at you) that isn't good. Mk4 vehicles aren't noted for rollover valve problems but you may have one. Was the damage on the Driver or Passenger's (fuel tank) side?
 
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Rembrant

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Mk4 vehicles aren't noted for rollover valve problems but you may have one. Was the damage on the Driver or Passenger's (fuel tank) side?

Damage was on passenger rear corner. It wasn't that bad...bumper cover, rear brake/signal light...but there was some metal damage beneath all that. These problems only showed up after the damage. Car works just fine, but I'd like to get rid of the code and be able to fill the tank properly.

What is the rollover valve?
 
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What is the rollover valve?

In the fuel tank expansion/ventilation system, at or around the top of the filler neck, is a valve that controls those devices. It's effectively a ball valve that shuts off the ventilation in the event of a vehicle rolling over, to try and prevent fuel escaping.
 
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Rembrant

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In the fuel tank expansion/ventilation system, at or around the top of the filler neck, is a valve that controls those devices. It's effectively a ball valve that shuts off the ventilation in the event of a vehicle rolling over, to try and prevent fuel escaping.

Ok, gotcha. I figured as much. I guess I have to start looking around in there...see what I can find.
 
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Jack@European_Parts

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I would verify a slow leak by doing basic tests.
First and foremost check the fuel cap for being OEM, seal in order and clicked tight.
A little Vaseline on the o-ring doesn't hurt for the gas cap to aid in a positive seal.

First run LDP tests which haven't passed in the readiness with VCDS.

Readiness: 0110 1101
These two tests below are shared by this readiness bit.

This test is run in 0x01-04-071 for LDP.
0x01-04-071 for EVAP
Verify the Evap N80 test and N80 valve are not stuck open by checking the valve for function during outputs and with the aid of a vacuum tester to verify it physically.

Testing the zone which supplied vacuum to the LDP circuit can be isolated with a vacuum tester.

Glass cleaner which foams........ can be sprayed on components, and seal areas while running the tests to see if you can see air escaping.
This is done while running the LDP via the 071 field in basic settings.
 
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Thanks Jack,

I will dig into it this weekend and see what I can find out. I have a couple dumb questions before I start...

LDP is mounted in the right rear wheel well, behind the plastic fender liner?
N80 valve is in the engine bay somewhere?
Any other major EVAP components I need to be aware of?
LDP pressurizes the system periodically to test for leaks?

Since I cannot fill the gas at normal (full) flow any more, I assume that my tank is either not venting, or the fill pipe is bent/kinked/etc.

Anyway, I'll get a look this weekend and run some tests, see what I can find. Was just trying to do my homework ahead of time.

Thanks again,
Rem
 
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Jack@European_Parts

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LDP is mounted in the right rear wheel well, behind the plastic fender liner? Erwin and yes ...........
N80 valve is in the engine bay somewhere? Erwin and connected to intake after TV.........
Any other major EVAP components I need to be aware of? Erwin and study system..........
LDP pressurizes the system periodically to test for leaks? Erwin and Yes it does to force vapors to charcoal and pulsed via the N80.

Erwin and yes ...........?????????????

The reed valve in the LDP pump ( noid ) is used to identify the ability to hold PSI to determine if tanks leaks.

Crimps can be done to isolate the zones before tank and verify tests good.
 
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Rembrant

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Erwin and yes ...........?????????????

Ok, Ok...I get the Erwin bit...you didn't use the RTFB term on me this time?...LOL.

Fair enough Jack, I appreciate the information you supplied thus far.
That's all I wanted.
I'll carry on with my troubleshooting and report back with what I find.

Best regards,
Rem
 
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Jack@European_Parts

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Yes that's true, however, RTFB is a term of endearment, not the negative way most interpret it.

:)
 
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Dana

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Glass cleaner which foams per Jack or just a heavy soap and water mix in a spray bottle works to locate leaks in a lot of cases. If you spray the entire area and then run BS 071 and 070 while testing just keep an eye out for ANY bubbles / foam. I'm pretty sure the rollover is sold separately from the entire tank - but depending on where the other end connects you may have to drop that tank a bit to get to stuff.
 
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Jack@European_Parts

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071 runs the LDP and determines if a small leak/large leak is present exclusively.

The 070 test is a pulse of the vapors via the N80 to the intake, and is seen by the ecu when it can deviate the OXS control to calibrate it usually with the rear OXS in command.

FACT

070 test can be ran with gas cap cracked or off and 070 will pass..................because it only needs very little vapors to make a deviation on the OXS.
 
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These two tests below are shared by this readiness bit.

This test is run in 0x01-04-071 for LDP.
0x01-04-071 for EVAP


This is done while running the LDP via the 071 field in basic settings.

hello, I like to understand this in bold black. How can I use this string? could you give me an example? is this something that should be used in any special VCDS instance? I know 071 is related to evap test. thanks
 
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Jack@European_Parts

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hello, I like to understand this in bold black. How can I use this string? could you give me an example? is this something that should be used in any special VCDS instance? I know 071 is related to evap test. thanks

Hello Victor .........Sure.

To see 071 LDP in action to become more proficient with the use of basic settings.

Reset DTC memory 0x01-02-05
Unscrew gas cap relieving PSI in tank from prior pump up.......... so test will commence. ( If reed is already closed the test will ABORT )

Verify the LDP by tightening gas cap and running the test 071.

You can do this over and over at idle on pre 2005 cars.......... to see how the test works, and the function of the other fields in 071, for the reed valve status.

On later 05> ON CAN cars.......... it is advised to make sure the vacuum is sufficient, by raising the idle, or a road test at 2500 RPM in a lower gear.

Otherwise, I have found it will in some cars........... always pend a small leak code, where the diagnostic path induces the small leak DTC.

With this test I personally crimp zones back to the tank from LDP..........
This is done to isolate the ability of the pump to make PSI and reed position.

Special NOTE: For 2010 > cars which support J909/G400 EVAP/LDP PSI sensor control unit and OoooooDsssss UDS pull down menu tests!

Integrated module known as J909 control unit and component G400 connected to engine controller J623

If this switch fails to report the " ( LDP ) Leak detection pump " " status of PSI in tank ", you could get excessive PSI built up in the fuel tank from the LDP being over run, or other devices damaged in the fuel system.

This in turn can cause a head PSI at the N80 solenoid of the EVAP system.

This is a known condition that leaves raw fuel presented to intake manifold,......... depending on height of fuel in tank, & usually after a fuel fill up causing a car to flood.

If this situation exists, be sure to change the N80, and dry the charcoal filter........... so you don't get unneeded DTC's for fuel mixture.
I have seen engines while sitting not running with this condition, causing a siphon effect.
Fuel is sent to the intake during a stuck open N80 filling intake.
It eventually will fill the crankcase with this excessive fuel....... diluting the oil sump quality, by turning the oil into a solvent!
It's not like these cars don't have ring and blow by problems already.:banghead:

NostraJackass predicts you will become very familiar with J909, and his buddies for function real soon, after warranty expires.

Hope that helps! :p
 
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hello, I like to understand this in bold black. How can I use this string? could you give me an example? is this something that should be used in any special VCDS instance? I know 071 is related to evap test. thanks

It's old VAG-1551/1552 "shorthand".

0x01 = Address Word 01.
04 = Function 04 (Basic Settings).
071 = Group 071.

So translated to VCDS:

[Select] -> [01-Engine] -> [Basic Settings-04] -> Group 071.

-Uwe-
 
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Jack@European_Parts

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Yeah I guess I'm the old man now............. since VAG shorthand is now OLD :D
I probably should have seen that and converted the shorthand.

Still an immature kid at heart though!

Note to self : Continue blowing up controllers............... to see what can and can't be done to them!
Always test theories outside the box of the thought to be known.
Where is the CRAZY icon or dunce cap?

Excuse me while I go stand in the corner voluntarily till milk time.
 
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victor35ma

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Hello Victor .........Sure.

To see 071 LDP in action to become more proficient with the use of basic settings.

Reset DTC memory 0x01-02-05
Unscrew gas cap relieving PSI in tank from prior pump up.......... so test will commence. ( If reed is already closed the test will ABORT )

Verify the LDP by tightening gas cap and running the test 071.

You can do this over and over at idle on pre 2005 cars.......... to see how the test works, and the function of the other fields in 071, for the reed valve status.

On later 05> ON CAN cars.......... it is advised to make sure the vacuum is sufficient, by raising the idle, or a road test at 2500 RPM in a lower gear.

Otherwise, I have found it will in some cars........... always pend a small leak code, where the diagnostic path induces the small leak DTC.

With this test I personally crimp zones back to the tank from LDP..........
This is done to isolate the ability of the pump to make PSI and reed position.

Special NOTE: For 2010 > cars which support J909/G400 EVAP/LDP PSI sensor control unit and OoooooDsssss UDS pull down menu tests!

Integrated module known as J909 control unit and component G400 connected to engine controller J623

If this switch fails to report the " ( LDP ) Leak detection pump " " status of PSI in tank ", you could get excessive PSI built up in the fuel tank from the LDP being over run, or other devices damaged in the fuel system.

This in turn can cause a head PSI at the N80 solenoid of the EVAP system.

This is a known condition that leaves raw fuel presented to intake manifold,......... depending on height of fuel in tank, & usually after a fuel fill up causing a car to flood.

If this situation exists, be sure to change the N80, and dry the charcoal filter........... so you don't get unneeded DTC's for fuel mixture.
I have seen engines while sitting not running with this condition, causing a siphon effect.
Fuel is sent to the intake during a stuck open N80 filling intake.
It eventually will fill the crankcase with this excessive fuel....... diluting the oil sump quality, by turning the oil into a solvent!
It's not like these cars don't have ring and blow by problems already.:banghead:

NostraJackass predicts you will become very familiar with J909, and his buddies for function real soon, after warranty expires.

Hope that helps! :p


Super... thanks for the explanation, actually I will try to do an EVAP test this way. on some Euro car we always use Snapon scanners bi-directional for this... but for VW and AUDI i need to use VCDS it is better tool, I just need to know how. Thank you.
 
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victor35ma

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It's old VAG-1551/1552 "shorthand".

0x01 = Address Word 01.
04 = Function 04 (Basic Settings).
071 = Group 071.

So translated to VCDS:

[Select] -> [01-Engine] -> [Basic Settings-04] -> Group 071.

-Uwe-

Super.... thanks again Mr Uwe. now I understand you guys when I see this again... OK

another maybe related question. What is the box in the pic, that is highlighted, for?

11206009_1296250533760104_1700703904552796228_n.jpg
 
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Uwe

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The Direct Entry box on this screen:

scm-installed.png


... lets you type in a control module address (like 01 for Engine) if you know that address, rather than having to look for the button in question. We did this way back when at the request to people like Jack who have all the addresses and function memorized. In fact, on the next screen that comes up after a control module opens, you can even type a function number (like '04' for basic settings).

-Uwe-
 
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