Touareg: 2004 V8
Join Date: Jul 2015
Second Vehicle: Still looking
Thanked 1 Time in 1 Post
Kessy Problem? Vehicle Shutoff While Driving
Hey guys/gals, this past weekend something very weird happened to me. I was driving home to the wifey Saturday evening. While at 60mph on the back roads, all of a sudden my engine shut off. No, there was no noise, no smell of antifreeze, no oil loss, just dead. I was able to pull over safely and so I started to investigate. One thing that was odd- key in the ignition but the gauges weren't activating (coming alive.) My first thought was something to do with the Kessy and Immo. Regardless, I still check the antifreeze (all there and no leaks) and also the oil (oil on stick and no sizzle when put on exhaust i.e. no blown head gasket.)
So at this point, it's time for a roll back call. I get it towed to my father-in-law's shop. After getting it in, the first thing I do is grab my laptop and run an ODIS scan. NOTHING! No comms with any module in the car. So this had me scratching my head (I'm still scratching my head a little.)
With it being late, I left it there to deal with it the next day. I go back and start looking and nothing is obvious. I keep a tool box in the Treg since I've owned it, NEVER LEAVE HOME WITHOUT IT! The next thing I check is to see if the engine seized, not that I really expected it anyway. I rotated the crank pulley and all is good. This led me to an electrical problem.
One thing I did notice the day it quit and the previous day driving, I thought I had smelled antifreeze. I know I had a slight leak during extreme cold weather around the alternator pipes. That's not what I smelled though, it was electrical but it didn't have that typical electrical burning smell.
The first thing I did was remove the battery ground strap in an attempt to reset the system to see if I could connect with ODIS or VCDS, no dice and now the key was stuck in the ignition- all fingers pointing to immo/kessy unit. Next I got on elsa and pulled up relay/fuse descriptions. All relays and fuses checked good in the plenum (engine bay) fuse box. Next I checked the SB (drivers side) fuse panel. Low and behold I have two blown fuses. SB26 & SB41. SB26 10a (Airbag control module, Motronic Engine Control Module (ECM), instrument cluster, brake/clutch switches, ESP, Mass Air Flow (MAF) Sensor.) SB41 15a (Access/start control module) Kessy. So now I'm on to something.
Next I look at wiring diagrams for the Kessy Access/start. I notice there are 2 relays one in the plenum chamber (engine bay) C20 - -J682- Power Supply Relay (terminal 50), and one under the dash D5 - -J329- Voltage Supply Terminal 15 (B+) Relay. I figure since I had the smell coming from inside the cabin that I can rule out the C20 relay in the engine bay. So now I'm looking at the voltage supply relay and the kessy. I obviously have a short going on.
I decide to put a higher amp fuse in the the dr side fuse panel on both positions 26 & 41. I go to a 20a on 26 and a 15a on 41. Key on engine off, I get gauges alive but then those fuses blow. Next I decide to go up again in amperage. 30a on 26 and eventually get to 30a on 41- I know, I know, you shouldn't do this as it risks starting a fire or seriously damaging electrical equipment. I did this because whatever is causing it, I wanted it to burn so I could identify the issue and repair it. With both 30a fuses in place they don't blow, however the ignition comes on for just a brief second, the mfi/gauges come alive for a second, flashes a couple times then off.
Next thing I decide to do is swap the voltage supply relay with another underneath the dash just to eliminate the relay giving the problem, no change so I ruled out the relay. So that led me to the Kessy unit.
I've read about the Kessy rebuilds of replacing the 2 mosfets and 6 .22ohm resistors. Here's where I run into a problem. My Kessy unit DOES NOT have the 2 mosfets and 6 .220hm resistors on this board. See my attached pictures. I did notice that there is an Infineon HITFET transistor that looks like the legs are burned at the solder/board junctions.
Has anyone else with this particular Kessy unit had/have the same thing happen to them? Were you able to repair it? Has anyone replaced this chip and the Kessy work? Since it's obviously toast at this point I figure I can't damage it anymore so I ordered some new chips to replace these. Only 2 were not available. I also felt the board after turning the ignition on and noticed the heat coming from that chip that's what leads me to believe that this is the issue. Does anyone else think there is another issue going on to check? The other reason I feel that it's Kessy related is the common battery drain I've been experiencing leading up to the engine power loss. Any insight/experiences with the same problem is appreciated.
This is my daily driver and only car so it is imperative that I get it fixed. Also has anyone copied the 93c86 eeprom and copied it to a virgin chip and soldered it to a used Kessy, install it and it work? That might be another option I explore if the chip replacements doesn't fix it. I do have my SKC from my ECU.
I am very sorry for the long winded post but I don't want to leave out any details. Still to this point, I am unable to do a VCDS/ODIS scan on the vehicle.