The Shoeman

2005 S430 4matic
278208 miles
VIN: WDBNG83J95A447365

Drove to work with no issues/symptoms and parked int a garage at 7:00 am. Go to car at 12:30 to sit in it, eat some food, and charge my phone while listening to music. This is my typical routine. This time though, I see on the dash "Coolant! Visit Workshop" I looked at the temperature gauge and it was not overheating and I have enough coolant in the system. Low Coolant gives a different error message. No big deal, probably just a gremlin so I shut the car off and go back to work. 4:15 pm, I get off the garage elevator and I hit the unlock button on my key as I'm walking up to the car. Then this happens......

All the directional lights start flashing quickly (faster than just pressing the Hazard Light switch). No response to any pressed buttons on the key. I manually unlock the driver's door with the metal key and put the key in the ignition slot to hopefully have it recognize it and stop doing whatever it's doing......no change at all. I turned the key to try and start the car and the fan under the hood starts going FULL SPEED. I removed the key from the ignition and the fan stayed on and at full speed. I then had to go into the trunk manually with the metal key and disconnected the negative terminal to the battery. (I have tools with me for work) obviously everything shut down. I reconnected the battery terminal and the lights started flashing and after turning the key the fan went full speed again....and once the fan is on, it stays on without the key in the ignition. I disconnected the battery again and waited a little longer before reconnecting it. No change.

I tried to connect my bluetooth OBD2 scan tool but it wouldn't connect.

Lots of errors appeared on the dash cluster. ESP, SRS, ABS....they were there before I disconnected the battery the first time at the garage.
I had it towed from the garage at Brigham & Women's Hospital to my home about 1 1/2 hours away (because of traffic) with the battery disconnected. Got it home and tried to connect my STAR computer to it and it won't. Tells me it can't connect/communicate (I can't remember which word was used) to the Electronic Ignition Module. I tried other ways to connect the STAR and nothing would communicate.

With the lights flashing quickly, it seemed like the alarm was trying to sound, but there was no audible alarm. Guessing it's the alarm siren finally quitting, I ordered a new one and I installed it tonight. Unfortunately, there are no changes in the symptoms. Everything is the same....So I pulled the #30 fuse to stop the fan from spinning.

Another thing I noticed was the STAR was telling me the voltage was low (11.5 volts) when the fan was running full speed. I put it on the charger overnight on the 2 amp setting, but I still get the same readings.

I don't want to continue to throw money at this without knowing the problem. I already guessed wrong with the alarm siren. I'm thinking a new battery is next, but I just got tis battery 12 months ago and haven't had any signs that it was screwing up.

I'm guessing the lights and the coolant error are separate, but does seem a bit ironic that they both appear right around the same time.


Does anyone have any ideas on what this could be?

Thank you all in advance.

The Shoeman

Bought a brand new battery..... no change. All symptoms are still there.

The Shoeman

Just wanted to let everyone know I figured it out in case anyone else gets into this situation in the future.

When the Alarm system went into 'alarm mode' with the lights flashing and unresponsive to my key buttons or the key itself in the ignition, it must have blown the fuse number F78.

This fuse being blown would not let the car be reset by putting the key in the ignition. After I replaced the Alarm Siren, nothing changed. I started checking different fuses related to the Anti-Theft system. I pulled the fuses and they didn't make any difference in the state it was in. I don't know why but I went back and actually checked the fuses and found F78 blown.

As soon as I replaced the fuse with a good one, the lights stopped flashing. I put the key in and turned it.....it started!!!

So I'm guessing it was the Alarm Siren that was the issue because all is working well now and nothing else was changed.. I'm keeping some spare fuses and plastic trim tools with me so I can changed the fuse quickly and not be stuck again.

wallyp

Thank you very much for closing the loop. That could be very useful to another owner someday.