2003 VW Passat GLS Sedan - Passenger Side Floorboard Wet - Warning Messages

**Patrick Welch** · 20-08-2014,04:56 AM

Hello all !
I have a problem that hopefully someone can help me out with.

2 weeks ago, airbag fault came on as well as STOP low oil pressure came on. I drove home which was right around the corner and let it sit for an hour and all was gone. No check engine light though the airbag light was still on. I reset this light along with all codes and figured it was some kind of a fluke (fyi, i had washed the car in the morning). All has been ok the past two weeks.
Now yesterday, I was driving it, while its raining, and all of a sudden it felt like there was a hard shift on the car, and Instantly received the airbag fault, and the STOP low oil pressure light. I shut the car off, and checked the oil etc, all looked ok. I started the car back up and realized that all was ok.

Oil pressure "was" a critical concern however, an external gauge was used and determined that the oil pressure was ok. There was no valvetrain noise etc.

When I pressed the brake pedal down, the RPM's dropped to 0, and the low oil pressure light etc came on, when I took my foot off the brake, the stop message disappeared, but the car was placed into Limp Mode. Last night, checked the passenger side floorboard (location of TCM), and it was damp. Pulled up the carpet and it was soaked. I have heard that a potential problem is that the drains from the sunroofs become clogged, forcing water into the ECM and TCM bays under the floorboard. Maybe a corroded connection?

After scanning with a v-checker scanner (cheaper version of VagCom), I pulled the following codes after the last issue which leads me to believe that it is in fact the wiring.
The car is running fine with no issues at this time while it is still dry out

P1854, HARDWARE DEFECTIVE
P1850 MISSING MESSAGE FROM ENGINE CONTROL
P1982 IMPLAUSIBLE MESSAGE FOR ABS CONTROLLER
P1626 MISSING MESSAGE FROM TRANSMISSION CONTROL
P1639 MISSING MESSAGE FROM INSTRUMENT CLUSTER

My biggest concern is to find out where the water is coming from. I know about the sunroof drains and how they clog, and I tested after cutting the ends of the tubes that come out of the door jamb by the hinges, and they are clear. I also checked the "area" of the drain underneath the battery, but did not see standing water so i figured maybe that was ok. Are their any other areas that maybe I should be looking for ?

Thank you for all of your support!

**Doctle Odd** · 20-08-2014,07:50 AM

Passat B5, B5.5 plenum drain cleaning

**Patrick Welch** · 22-08-2014,03:24 AM

Thank you for your help. I will check it out and see if its the culprit. One day I checked and I could see water down in there... and the next day I checked and nothing. No new water inside the car. This is really the first problem I have had with it.. though I have only had the car since December. Not a good sign so early. Only 110,000 on it

**Patrick Welch** · 24-08-2014,06:01 PM

Ok, so I havent actually taken the battery out yet, but I wanted to make sure I was on the right track before I did. It was completely dried out in both the vehicle carpet, and the area that the battery is sitting around in. After I got a car wash this morning, I checked the battery bay and there was a little water in there, and I checked the floorboard which I still have the carpets pulled back in, and there was a little bit of water in a stream that was seeping into the floorboard towards the TCM. Its not coming from where I thought it would so I just wanted to make sure that I was on the right track.

Thanks !
Attachment 25442

**Doctle Odd** · 24-08-2014,06:40 PM

It won't have dried out unless you removed the carpets, there's 2 inches of underlay under the carpet. Follow Big Col's write up for the plenum chamber and cabin filter seal. Battery has to come out at least once so you can see what you have to do. You need a special tool to clear them you can make it from a wire coat hanger. If you don't get the carpets out and dry the car properly you'll ruin the CCM eventually

**Patrick Welch** · 24-08-2014,06:43 PM

I did remove the carpets, they have been completely dry including the underlay for about a week now since my first post. The carpet has been propped up with a 2x4 so i could keep checking to make sure it was completely dry. I will just remove the battery to take a look , thanks

**Doctle Odd** · 24-08-2014,08:19 PM

Don't forget to check the cabin filter seal when the plenum cover is off

**Patrick Welch** · 25-08-2014,02:44 AM

Originally Posted by Doctle Odd

Don't forget to check the cabin filter seal when the plenum cover is off

Ok, so I took off the plenum cover, removed the battery, and its as clear as could be. It looks like someone was already in there as the grommet that i think it supposed to be in there was removed and I poured a gallon of water down in the compartment and drained out onto the ground fine.20140824_203341.jpg 20140824_203348.jpg

What do you mean by the cabin filter seal?
I removed the cabin filter itself on the left side of the engine compartment. I'm guessing if I take the three screws out and pull the whole thing out of it then there will be a seal under there? is that what goes bad? I put another gallon of water directly onto the windshield directly above the cabin filter after I got everything back together, and looked into the inside of the car and didn't see any water coming inside. I also poured water directly on top of the sunroof and the drains appear to be working fine coming out of the door jambs. One thing that I did notice that on the front passenger side sunroof drain where it exits out of the door jamb, the grommet thats built into the drain was pulled away a little bit from the door jamb. I left it like this and poured was directly on top of this purposely hoping that was would go inside of the car but it didnt once again. I pushed the grommet into place, and here I am completely stumped. Any ideas?