Your Video - Mercedes-Benz E500 No Start,(No Communication with PCM)

Hi,

My Vehicle is a 2003 E500 Mercedes.

I stumbled across one of Dan's videos (Subject Line) while attempting to correct a no start, with high fan speed condition. I really like your approach Dan, and thought you might be able and willing to give me some guidance.

My condition is similar to your video situation, but in my case, there is no voltage on the Red/Blue Wire, where in your video you experienced no voltage on the Red/Violet. I jumpered the two as did you, but that blew the 7.5A Fuse (#42) in the left-side dash panel. That could make sense simply due to that Red/Blue circuit (larger wire) needing more current than that fuse would allow. Still It makes me nervous, and I don't want to cause further damage.

I should probably back up with some details. This all started after I hit a large raccoon at 60mph. It messed up my lower cowling, and punctured the radiator. I managed to get it all back together with a new radiator even though the AC condenser is also warped. It took me a couple months, figuring out all the parts I needed to order and working outdoors when it wasn't too blazing hot out, and then extended into the cold season. Along the way, for no apparent reason one day my battery was dead. I checked for cabin lights etc., recharged the battery and again, overnight it discharged so low that it wouldn't take a charge. I took it to my battery shop and they used their mega charger and brought it back to life.

I then decided I should change out the transmission fluid and filter while I had the car in the air, as I do plan on keeping this car indefinitely. Side note, but as I was under the car working on the transmission pan, I began to hear some sort of cycling noise, fairly loud that sounded as if some sort of servo motor was trying to bring action. I wondered if that was the cause of my battery dying, but since in the middle of a transmission pan drain I didn't try very hard to isolate the source of the sound. Finishing up, I brought the car down off the ramps and to my sorrow, noticed that it was sitting low, almost on the tires. I had had a bit of trouble with that problem before the raccoon, and figured that it would pump back up and hold as it had in the past.

No luck getting it back into a drivable height, so I undertook fixing the airmatic system. In your case they had removed the air struts. I was unable to determine (hear) if the compressor was running or not and first removed the wrong fender panel trying to get access. Frustrated at that move, and not enough time to open up the driver side panel I began pulling and removing all the fuses and relays in the engine compartment hoping to stimulate some action of the compressor. Stupid plan I know, but it was nice of the dash display to tell me what system I had disabled after pulling a relay and turning the key. BUT...I got more than I bargained for and up came the dreaded ESP Malfunction, Visit Workshop message (A brand new Message). Replacing the relay did nothing in remedy and ever since I have been dead in the water.

So, all of that background just in case it has bearing on the overall root cause. Prior to that it was starting and running, no problem, so in my mind the no start condition is due to my foolish pulling of relays and fuses, without disconnecting the battery in between or something. Since that time I have pulled and verified function of all fuses and relays in the engine compartment. For each relay, I applied 12vdc to the coil and noted continuity on the switch contacts, so I am confident they are all operational. All fuses are fine as well.

After watching your excellent video, I had additional hope and methodology, but as I said I've blown fuse 42 and it scared me. With quick touches of power from the other wire, I could hear clicking of a relay towards the center of the motor (Throttle Body?). Looking at a screen shot of your video (attached) though blury, I am able to somewhat discern what circuits we are concerned about. I have no voltage on either side of fuse 43 (15A Engine compartment). That leads me to question the relay (#7 on the diagram), but I am not certain which relay it is per the fuse box diagram (probably I or K). I have also checked the Pre-Fuse box under the carpet on the passenger side Front. The access was so damn impossible such that I have since only peeked at the Rear Pre-Fuse Box in the trunk because it looks to have similar access difficulties. It would make sense to check there, but my confidence and energy have waned, and I see no reference on the diagram to the rear box related to the Red/Blue circuit.

So I am hopeful that you can still dig out the schematic, and I guess my primary questions are:
1) Where does the power (5V or 12V ?) originate to energize the uncertain relay, and Fuse #43? I can't see the diagram well enough to decipher the source of the wires to the relay, though one lead says Left Front Footwell (What does W15/2 mean)?
You mentioned a Power Distribution schematic?
2) And where do the other 2 wires for that relay come from, (ckt #1 and #14 I think, hard to read)? Are they grounds?
3) Were does the Hot At All Times power come from? A Buss in the fuse box I'm guessing.
4) What causes Relay R7 to energize? The turn of the key? In other words, would fuse #43 only have power with the key on?
5) Is that circuit to fuse #43 to have 5 volts, or 12 vdc?
6) How did you decide that those two red wires were "power" for the computer? Just because they were red? There are no +5 or +12 symbols on the schematic.
7) What would you do next?
And of course, once I get the car running again, I still need to figure out why the Airmatic struts are not inflating. I can't find leaks etc. without the pump working.


I really, really just want my car back. I have been without it and driving my truck for months. Appreciate any advice you or any of your viewers can offer.

Curtis

If anybody actually reads all this... im sorry ur that bored

Sorry for the book - Not bored, just desperate. Having all the background might stimulate someones idea of where the problem might originate.
To simplify, why does fuse #43 have no voltage. From where does that power originate, and under what circumstances, ie. key on, or other condition?

Thank you, that gives me somewhere to check. Of course it would be the one zone I figured could have no bearing on the front fuse box, but hey I guess it makes sense, with the battery origination being in the trunk.
Would have checked there by now, but weather has been vile in Kansas City. Tomorrow is to be sunny and warmer, I'll get to it.
And those schematics are from being a member of a particular repair website? Saw it somewhere, but lost track of it. Appreciate the excerpts.
Thanks Again.