Volkswagen Passat Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
We had some very heavy rain, and I found about 1" of water in the driver's foot well. Vehicle was parked on a slope, front facing down. The car did start after mopping up and I flipped the car around in the driveway. Then the alarm goes off but it's not beeping, just sounding continuously, so some sort of electrical short obviously. I pulled fuzes and it stops deafening me and the neighbours.

Then I go online and do some reading and find the Comfort Control Module is under the driver's feet, because German engineering. So I go and pull off the various panels and carpet and pull out the CCM and unsurprisingly it's now corroded as the 'waterproof' box was full of water.

Smallish problem with the CCM, but now I have a bigger problem, the car doesn't crank anymore. Battery voltage reads 12.4 V, all the proper dash lamps show, no weirdness with the automatic transmission lamps indicating that box on the other side is wet. It's posting no codes.

I cannot hear any relays switching when I turn the key. Checking the relay panel I have no relay in slot 12 and one in slot 13, a #53 which is the starting interlock relay-clutch position. I pulled the relay out and took the cover off, put it back in, held it closed while turning the key, still no crank. I've tested the resistance of the 15 A fuzes that are indicated as being part of the engine functionality, they're all ok.

Do I need to replace the CCM first?

Anything in the big wire bundle that might have also corroded?

Any other thoughts?
 

·
Moderator/Administrator
Joined
·
25,593 Posts
Check all the fuses and make sure the CCM is plugged in. Fuse 14 is a common culprit. Replace it, even if it doesn't look blown.
 

·
Registered
Joined
·
28,620 Posts
Yes, there are many points where wires are spliced that can corrode. If the fuses, cleaning/drying the CCM (and plug) does not work, you may need to start unwrapping the wires to check all of the splices.
 

·
Registered
Joined
·
2 Posts
Discussion Starter · #5 ·
Well I fixed the CCM by etching it in pickling vinegar + salt for about 30 minutes, then neutralizing with a baking soda solution, then rinse, then put it in the oven covered with a towel for about 30 minutes at 170 F. The cable housing/plugs I also soaked in vinegar in a jar, then neutralized, then put in front of a space heater for an hour. Car started right up again, all the windows/sunroof/locking features seem to work fine. Looking at the board its showing bare copper in some places on the pins so I'll have to tin it a bit with solder.

Planning on putting the CCM somewhere in the console, if nothing else I'm sure there's space where the owner's manual is supposed to go. I think I should also move the automatic transmission module somewhere safer too.

Does anyone know if parking on an incline exacerbates the sunroof drainage issues? I was parked with the nose downhill but it seems like it's marginally safer to be parked with the nose uphill?
 

·
Registered
Joined
·
10,170 Posts
I suggest you fix the water ingress problem, and leave the control modules where they are.

Completely unwrap all of the CCM harness and pull the wires apart to find the splices, any corroded splices need
to be cut back, soldered, and covered with marine grade heat shrink tubing. (You might need to add short wires to replace what you cut out)
Also check ground connections (1 on floor and on "A" Pillar), and check CCM/TCM and "A" Pillar connectors.

Have a good look at this link, before you start. (Note: This is a UK car, the CCM is always on the LHS)

This thread attempts to bring together all the problems regarding water ingress and their solutions.
Water Ingress and Solutions
 

·
Registered
Joined
·
28,620 Posts
Parking on a an incline can make the difference until you can repair the problem, but only if you know where the leak is. We had a leaking sunroof drain tube that only leaked while the front of the 05 Golf was uphill in our driveway. We ended up backing the car in over the next year until I had the problem repaired. I had already cleaned all of the drains and made sure everything was plugged in, but it still leaked between the rubber grommet on the sunroof and the plastic drain hose. I had the shop seal all grommets to the hoses at each corner while they had the headliner down for replacement.
 

·
Registered
Joined
·
8 Posts
like cchief22 said, seal the board with clear coat or silicone potting and put some silicone grease to the plugs, water or not it should never be a problem again and you dont need to relocate, this wont do anything for the wires/loom but the module will be safe, i did the same thing when i got my new module after mine got wet and was beyond saving
 
1 - 9 of 9 Posts
Top