markm432

So i've had a problem starting my car for a while, and I found the cure...

I had it hooked up to a scanner several times, including once at Mercedes, and even they were perplexed. Checked fuel pressure, plugs, wires, starter, battery, fuel filter, replaced CPS, etc... nothing. However, when I tried switching the 12v relay that is under the hood, with the fuel pump relay, bam, started right up every time. And, I didn't have to buy a new relay to find out that's the problem. When I switched the relay the car started fine, but then I got the ESP, BAS, ABS malfunction. So I bought a new relay, so they were both good, and that problem was gone. So a word to the wise, before going through hell as I did, first just swap those two relays and see if the problem is gone, it's free and takes 30 seconds. Also swap them if you are getting the BAS, ESP, ABS malfunction just in case it's not the break switch.

software

Thanks for the tip!

How many miles are on that car and what year is it?

markm432

welcome, hopefully it will help some people.

It's a 2000 320 w/ 100k miles, but it's real clean and runs great.

The Jury

Only starting issue I have seen is a very minor one. The transponder doesn't seem to always signal the ignition properly and I have to push the key in a little more. Batteries are good in the transponder (new, but that wouldn't matter anyway) so I blame it on the tip being scratched from heavy use. It's only a slight delay when I turn the key (half a second or so, just enough to notice it).