Check Engine Light Code P0442
#26
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Location: Irvine, CA
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2013 E350 Bluetec, 2008 Audi S4 Avant, 2011 VW Golf TDI, 2015 Audi S3, 2020 GLB250
This just happened to my '05 C230. I have extended warranty, but apparently, the fuel filler neck is not covered, and the cost of parts and labor is $850.00 from Fletcher Jones. On a side note, MBZ extended warranty has been pretty useless so far...0 for 2 so far on warranty claims.
#27
Senior Member
For you Coupe guys-
I pulled out my Fuel Filler and leaked checked it in a bucket of water with a small amount of pressurized air.
No leaks found, more searching!
Here is what the Fuel Filler looks like-
F= Front as you would be looking at it after removing the Right Rear Wheel.
R=Rear as would be the back side of the Fuel Filler that is against the body.
I pulled out my Fuel Filler and leaked checked it in a bucket of water with a small amount of pressurized air.
No leaks found, more searching!
Here is what the Fuel Filler looks like-
F= Front as you would be looking at it after removing the Right Rear Wheel.
R=Rear as would be the back side of the Fuel Filler that is against the body.
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C3Duece (08-15-2020)
#28
Super Moderator
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For you Coupe guys-
I pulled out my Fuel Filler and leaked checked it in a bucket of water with a small amount of pressurized air.
No leaks found, more searching!
Here is what the Fuel Filler looks like-
F= Front as you would be looking at it after removing the Right Rear Wheel.
R=Rear as would be the back side of the Fuel Filler that is against the body.
I pulled out my Fuel Filler and leaked checked it in a bucket of water with a small amount of pressurized air.
No leaks found, more searching!
Here is what the Fuel Filler looks like-
F= Front as you would be looking at it after removing the Right Rear Wheel.
R=Rear as would be the back side of the Fuel Filler that is against the body.
#30
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2013 E350 Bluetec, 2008 Audi S4 Avant, 2011 VW Golf TDI, 2015 Audi S3, 2020 GLB250
#31
Senior Member
You guys are going to love this-
As I stated in my earlier post that there was no leaks found in the Fuel Filler Assembly and more diagnosis was needed.
I pulled the Charcoal Canister as it would not hold a vacuum.
Got it on the bench and could hear hissing when trying to pull a vacuum from around the bottom of the Charcoal Canister Shutoff Valve.
Removed the Shutoff Valve and a picture is worth a 1000 words- Deteriorated O-Ring!
Called up the dealer and ordered a new O-Ring, $3.25.
Will be here on Tuesday.
As I stated in my earlier post that there was no leaks found in the Fuel Filler Assembly and more diagnosis was needed.
I pulled the Charcoal Canister as it would not hold a vacuum.
Got it on the bench and could hear hissing when trying to pull a vacuum from around the bottom of the Charcoal Canister Shutoff Valve.
Removed the Shutoff Valve and a picture is worth a 1000 words- Deteriorated O-Ring!
Called up the dealer and ordered a new O-Ring, $3.25.
Will be here on Tuesday.
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C3Duece (08-16-2020)
#32
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Very interesting - Bet the dealer would have replaced the charcoal canister.
#33
MBWorld Fanatic!
#34
Senior Member
That's what i'm thinking.
When i get the new O-Ring on Tuesday from the dealer, I will post the part number.
It's so easy to change the O-Ring, 1 hour tops.
Actually I think you could change the O-Ring with the Charcoal Canister still installed in the car.
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C3Duece (08-16-2020)
#35
MBWorld Fanatic!
Pictures please!! I know you already have it out but could you take a little extra time and see if you really could replace the O-ring without removing the canister? TIA
#36
Senior Member
#38
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#40
Senior Member
Ok for you Coupe Guys,
Here's a picture of the package that the O-Ring came in with the Part Number.
Picture of the "Tab" Lock that locks the Canister Shutoff Valve into the Charcoal Canister, it's like an Electrical Connector to remove.
Also pictures of the Mounting Bracket for the Charcoal Canister and the Back Side of the Charcoal Canister.
The Charcoal Canister has a tab that you pull with your finger, no tools needed, and then you just lift the Charcoal Canister up and out to remove it from it's bracket.
I'm not going to recommend to replace the O-Ring with the Charcoal Canister in the car, although it can be done.
It's much easier to remove the hose from the Top of the Charcoal Canister, just need Pliers, its a constant tension clamp.
Then remove the Electrical Plug Connection at the Canister Shutoff Valve, then pull the little Tab towards you and just lift up and out to remove the Charcoal Canister.
You do not need to remove or disconnect the Small Purge Line at the Bottom of the Charcoal Canister.
Change your Cracked O-Ring with this Updated Part Number O-ring, my cost $2.60 that still cracks and you are done.
Reinstall the Inner Fender Apron and Passenger Side Rear Wheel.
Hope this helps,
Dave
Here's a picture of the package that the O-Ring came in with the Part Number.
Picture of the "Tab" Lock that locks the Canister Shutoff Valve into the Charcoal Canister, it's like an Electrical Connector to remove.
Also pictures of the Mounting Bracket for the Charcoal Canister and the Back Side of the Charcoal Canister.
The Charcoal Canister has a tab that you pull with your finger, no tools needed, and then you just lift the Charcoal Canister up and out to remove it from it's bracket.
I'm not going to recommend to replace the O-Ring with the Charcoal Canister in the car, although it can be done.
It's much easier to remove the hose from the Top of the Charcoal Canister, just need Pliers, its a constant tension clamp.
Then remove the Electrical Plug Connection at the Canister Shutoff Valve, then pull the little Tab towards you and just lift up and out to remove the Charcoal Canister.
You do not need to remove or disconnect the Small Purge Line at the Bottom of the Charcoal Canister.
Change your Cracked O-Ring with this Updated Part Number O-ring, my cost $2.60 that still cracks and you are done.
Reinstall the Inner Fender Apron and Passenger Side Rear Wheel.
Hope this helps,
Dave
Last edited by drb930; 08-13-2009 at 12:20 AM.
#42
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Because the fuel filter contains the fuel system pressure regulator valve on V6 models
#43
It's not just the V6.
All the petrols use a fuel filter with 4 connectors marked as:
PUMP: Inlet from pump
MOT: Outlet to motor
TANK: Return line to tank (From the build in pressure regulator valve)
CAN: Connects to carbon canister
Ny question is, what does the CAN connection do?
All the petrols use a fuel filter with 4 connectors marked as:
PUMP: Inlet from pump
MOT: Outlet to motor
TANK: Return line to tank (From the build in pressure regulator valve)
CAN: Connects to carbon canister
Ny question is, what does the CAN connection do?
#44
MBWorld Fanatic!
#46
I don't think you are right mleskovar.
I have cut opened a fuel filter and actually the CAN connector goes to nowhere.
![](http://www.aclassinfo.co.uk/fuel%20filter%20cutaway.JPG)
It is sepparated by the rest of the filter using a rubber membrane.
When pressure from the pump builds into the filter, the spring is pushed back, opening the pressure regulating valve and excess fuel goes back to the tank.
When the valve opens, it pushes the membrane up a bit and this creates a positive pressure inside the CAN line.
I do not know why this is
I have cut opened a fuel filter and actually the CAN connector goes to nowhere.
It is sepparated by the rest of the filter using a rubber membrane.
When pressure from the pump builds into the filter, the spring is pushed back, opening the pressure regulating valve and excess fuel goes back to the tank.
When the valve opens, it pushes the membrane up a bit and this creates a positive pressure inside the CAN line.
I do not know why this is
#47
Ok for you Coupe Guys,
Here's a picture of the package that the O-Ring came in with the Part Number.
Picture of the "Tab" Lock that locks the Canister Shutoff Valve into the Charcoal Canister, it's like an Electrical Connector to remove.
Also pictures of the Mounting Bracket for the Charcoal Canister and the Back Side of the Charcoal Canister.
The Charcoal Canister has a tab that you pull with your finger, no tools needed, and then you just lift the Charcoal Canister up and out to remove it from it's bracket.
I'm not going to recommend to replace the O-Ring with the Charcoal Canister in the car, although it can be done.
It's much easier to remove the hose from the Top of the Charcoal Canister, just need Pliers, its a constant tension clamp.
Then remove the Electrical Plug Connection at the Canister Shutoff Valve, then pull the little Tab towards you and just lift up and out to remove the Charcoal Canister.
You do not need to remove or disconnect the Small Purge Line at the Bottom of the Charcoal Canister.
Change your Cracked O-Ring with this Updated Part Number O-ring, my cost $2.60 that still cracks and you are done.
Reinstall the Inner Fender Apron and Passenger Side Rear Wheel.
Hope this helps,
Dave
Here's a picture of the package that the O-Ring came in with the Part Number.
Picture of the "Tab" Lock that locks the Canister Shutoff Valve into the Charcoal Canister, it's like an Electrical Connector to remove.
Also pictures of the Mounting Bracket for the Charcoal Canister and the Back Side of the Charcoal Canister.
The Charcoal Canister has a tab that you pull with your finger, no tools needed, and then you just lift the Charcoal Canister up and out to remove it from it's bracket.
I'm not going to recommend to replace the O-Ring with the Charcoal Canister in the car, although it can be done.
It's much easier to remove the hose from the Top of the Charcoal Canister, just need Pliers, its a constant tension clamp.
Then remove the Electrical Plug Connection at the Canister Shutoff Valve, then pull the little Tab towards you and just lift up and out to remove the Charcoal Canister.
You do not need to remove or disconnect the Small Purge Line at the Bottom of the Charcoal Canister.
Change your Cracked O-Ring with this Updated Part Number O-ring, my cost $2.60 that still cracks and you are done.
Reinstall the Inner Fender Apron and Passenger Side Rear Wheel.
Hope this helps,
Dave
so...
this took care of your checkengine ligth ???
i got the same code , i already replaced the gas cap , but the code came back...
![smash](https://mbworld.org/forums/images/smilies/smashfreak.gif)
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C3Duece (08-16-2020)
#50
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2007 cls63 AMG
I took apart the canister valve and checked the o-ring. It looks like brand new and is in good shape. Replaced everything, check engine light is still on.
How do you check the purge valve to see if it is working right?
How do you check the purge valve to see if it is working right?