2003 Passat: CCM and fuel filler flap release electrics + Bentey manual

[JohnPierpoint]

I've posted in other threads about problems with the CCM on my Passat. I still haven't resolved these yet, but I'm posting this question about the wiring to the fuel filler cap, as the circuit diagram in Haynes doesn't explain how the CCM is involved. I'm a bit confused!

The diagram shows the filler cap solenoid getting its live feed from the fuel cap switch. This in turn is fed from a star point, which in turn is connected to a fuse (F36, 15A). The fuse goes right back to the battery 12V.
The CCM only seems to be involved with the illumination of the switch. It feeds a bulb that sits in the same housing but is electrically separate from the switch circuit.

So what I don't understand is why when the CCM is faulty or removed (or the wires to it are damaged), this stops the fuel flap release from working.

Maybe the simple answer is just "Haynes is wrong"!

Does anyone have (or know where to find) a decent wiring diagram that covers the CCM for this model?

I was thinking of splashing out on a Bentley manual set as these seem to be more detailed than the Haynes ones; but as I'm currently unemployed, I don't want to spend this sort of money on a blind purchase without some recommendation. Has anyone used these manuals for electrical repairs, and can they recommend them?

[martin1810]

If you send me an email address I'll send you the circuit diagram. Don't expect miracles. VW don't release data for the internal ccm control.

[JohnPierpoint]

Many thanks for the info Martin. Very useful!
Still very confused about the role of the CCM in the filler cap solenoid circuit though.

The good news is that I now have access to the solenoid, so I can manually release it.
For anyone else with the same problem on an 03 Passat estate, here's how to get at it:
Take the panel off the hatch for the emergency kit in the boot, driver side. Remove anything stored in there.
Undo the screw at the top of the plastic moulding that holds the items in place.
Carefully bend and pull the plastic moulding down and out from the top until it just pokes out past the boot lining.
It should now be possible to see the solenoid housing, and get your hand in. Reach around behind the housing until you can feel the solenoid shaft where it hooks onto the flap release.
Pull this back with two fingers, and the flap should release.

It may be possible to fit some sort of pull-cord to this. I'll investigate. . .

Getting enough access to the solenoid to remove it (or to rewire it) may still be tricky, as it's behind the weel-well. It probably requires removing the whole boot-liner and all the plastic trim on that side.

[KieranM]

I have a B5 estate, the fuel cap release wiring to my switch is the bit that is dodgy, I also had a broken solenoid, by the way it was worth buying these from the dealer, as second hand ones are just as expensive on fleabay.
My current solution to getting my fuel cap release switch to work is.

1. Stop the car
2. Handbrake on
3. Poke a finger in the gap underneath the handle of the handbrake, rotating finger towards yourself
4. Tickle some wires
5. It works

Replacement switches are cheap enough, but I'm pretty damn sure it is the wiring to it that is my problem, the centre console comes out with out too much hassle. As it stands though as long as the tickling method works, that'll do.

[wmcalin]

Also having issues opening the fuel cap, have noticed the cap will only release now if I have the drivers door fully open.
When I purchased the car the fuel cap would open if the door was open or closed.
Does anyone know where the cabling goes from the fuel release switch, does this go directly to the CCM

Any help would be great.

[caldirun]

I have a B5 estate, the fuel cap release wiring to my switch is the bit that is dodgy, I also had a broken solenoid, by the way it was worth buying these from the dealer, as second hand ones are just as expensive on fleabay.
My current solution to getting my fuel cap release switch to work is.

1. Stop the car
2. Handbrake on
3. Poke a finger in the gap underneath the handle of the handbrake, rotating finger towards yourself
4. Tickle some wires
5. It works

Replacement switches are cheap enough, but I'm pretty damn sure it is the wiring to it that is my problem, the centre console comes out with out too much hassle. As it stands though as long as the tickling method works, that'll do.

On an 03 Passat the fuel flap release switch is in the drivers door!

[caldirun]

Also having issues opening the fuel cap, have noticed the cap will only release now if I have the drivers door fully open.
When I purchased the car the fuel cap would open if the door was open or closed.
Does anyone know where the cabling goes from the fuel release switch, does this go directly to the CCM

Any help would be great.

I am quite sure all the CCM wiring goes via the plug and socket array on the lower A post, passenger side.
The flap release switch will be just signal wiring, the output to the solenoid will be from a driver in the CCM, a relay may be in this circuit, check the Elsawin current flow diagram for details.
From the door open/closed effect it is sure to be the signal wires going through the rubber flex from the A post to the door that have broken

[KieranM]

On an 03 Passat the fuel flap release switch is in the drivers door!

I didn't know that until my recent purchase!