Intelligent Key System Warning Light...

Originally Posted by Joeld0803

I ran into this issue just recently on my 2010 370 convertible. never had a problem and 78,000 miles on it. I parked the car recently close to the building to avoid direct sun throughout the day but a torrential rain came that afternoon and the car was then parked under a water fall.

I moved it to prevent flooding but on the way home I noticed this Key light by my fuel guage came on and I started having starting issues. I read all these posts about the steering lock and the IPDM and the horror stories and thought to myself geeeze that is an expensive repair at the dealer. My lock was working as I could hear the mechanism work under the dash but yet the light was on and push the button and no crank. I found that if I got in the car and held the brake and poked the button one time from the get go with the brake applied it would crank and start and then the light would come on for the key. If I shut it off and tried again it would not start. Recycled everything form a start point of getting in the car and pressed the brake and poked the button one time it would start. The key being in the fob holder had no bearing on it whatsoever.

I decided to go to the IPDM module first since it was exposed to all that rain water hammering my windshield and going down the back side of the hood. As I was removing it I shook it and water was coming from it. I removed it and disconnected all connectors. separated it from the black shield cover and then removed all the fuses and relays laying them out in order according to location. I pried the white box apart and cleaned it down with electric cleaner both on the circuit board as well as the pin sockets and inspected for damaged pins and solder joints on the board. Some of the sockets appeared to have mildew traces and the fuses appeared to have a white corrosion scale on them and I assume some of it was from natural humidity over time. I set the circuit board on a towel on a oven pan and set the temp on my oven to 280 degrees and let it warm up. Turned the oven off and inserted the pan in the oven for 15 minutes to dry the circuit board. Removed and reinstalled all fuses, relays in original position. reinstalled in the car and tested and the light is out now and everything is working fine.



If the steering lock mechanism is working and you can hear it and your light is on and the engine has cranking issues I would highly recommend removing and cleaning the IPDM as well as all wire connections and fuses with electrical cleaner. just saved about 700.00 at the stealer from what I have been reading about this issue.

I drove it into work 50 miles one way this morning and the light remained out the whole time and it fired right back up after getting here. the light was coming after about 5 miles of driving before but sometimes sooner and sometimes later as whatever connection issue in the IPDM was intermittent. Just clean it up as best you can and dry it and reinstall. Took me about 2 hours but saved me alot.



Just a suggestion.