I have owned my 1997 E420 for 13+ plus years and have put on most of the 94,000 miles that she has on it.*She has never given me any major problems.*

A few weeks ago I decided to sell her. Well this week she decided that she did not want to leave home, she dose not want to start. Go figure!

She will turn over but will not start.

Here is what I have done.

* * *My wife had run the gas tank down to the point the gas light came on, so I though maybe gas. I put in 5 gallons. No change.*
* * *Then i thought gas filter. I had never replaced it before so I went and changed the filter out. No change.

* * *I got on the Internet and read, read and read.

* * *The first thing that came up was the CPS. Ok I got a Bosch CPS from ********AZ and put that in. No change.

* * * Next I check the fuel pump. I check to see if I am getting power to the pump when I turn the key on. It does not look like I am getting power. So just to double check the pump I hook it up to a battery and it runs.

* * *It looks like my fuel pump runs but am I getting the pressure I need? I go out and buy a fuel pressure gage. I hook it up and turn the key on. No pressure. The pump is not running. I found out that you can jump the fuel pump relay at the k40 relay by pulling the B connection plug and jumping wire 1 to 3. *I do this and I get 50+ psi, and it holds there. So I think the fuel pump is good and my fuel injectors are not leaking.

* * *Ok I think I may have the problem. The K40 relay. I take it out and look at the solder joints looking for a bad one. No luck. I have what looks like a perfect K40 relay. This still could be my problem.

* * *I think maybe it's time to see if I can get any fault codes. I run out and buy a Actron CP9550 code reader. I follow the instruction and can only get a link error. I follow the instruction for this message and still get a link error. I call Actron and ask them what to do. The tech was no help, he said the car had to be running to get a reading. That did not make any sense to me so I got back on the Internet and found out that if you have a problem with you ECM you may not be able to get fault codes.

* * *So with all that being said, does anyone have any suggestion of where I should go from here?

Thanks,
Domenick

* * *

Try a different key.

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I have 4 original keys. I tried 3 of them. No change. From what I have read the car would not even turn over if it was the key.

Thanks for the reply
Domenick

I believe it could be the K40 relay. But before I replace it, I would like to know more about it.

What is the power sorce that activates the k40 relay?

What else does the K40 relay operate?

If I have a problem with my ECM would the K40 relay still work?

If I am not getting spark to the plugs, is that also controlled by the k40 relay or by something else? If so what?

Thanks,
Domenick

Check your production date. On all 1997 MBs the authorization system is DAS X, an unauthorized start an a DAS X 210 will give you no fuel injection, but it will CRANK (on a 202 there is no crank, but you have a 210). This started 6/96 production, I assume since yours is a 1997 that the prod date should be after 6/96, but double-check.

I was asking if you were getting messages in the odometer area.
On this car, actually you get unauthorized signals via the red and green LEDs in the rear view mirror. I am not sure what the sequence would be, but should spell it out in the owners manual, or maybe someone else will chime in. But probably both will blink at the same time(this is my best guess) or might alternately blink red and green.

DAS X has a seperate module, once it is satisfied the key is correct it authorizes the ECM to start. So possible it is the DAS module but I wouldn't go replacing things without knowing diagnosing things, that's just stupid.

PS DAS X is an oddball one-year only DAS

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Thank for the reply.

I check the production date. It is 3/97.

Both my remotes seam to be working just fine.

Thanks,
Domenick

Don't confuse the remotes working with the engine starting though.

Are the red and green LEDs doing anything when you are attempting to start the car, this is sort of important.

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Nothing is happening to the lights on the rear view mirror as i try to start her. The only time those light come on for me is when I point the remote at it and push the arm or disc arm button on the remote.

Thank,
Domenick

It's unusual that there is no flashing at the mirror when trying to start. I would think possibly the DAS module, but again not the kind of thing you want to just "try", so might have to get it to a shop so they can put the computer on it.
As a test of the DAS module you can see if the alarm works, for example. Roll down the drivers window, lock the door with the remote, wait awhile, then try unlocking the door by pulling up on the lock knob and see if the alarm goes off.

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Just tried the alarm. It worked as it should.

Based on what I have checked could this be the K40 relay? Or is there anything I have done that would ruled it out? If the K40 relay has a problem should I still get power to the plugs?

Does anyone know if I would still be able to get a code readout on my code reader even if the k40 relay was bad? Or link error is more likely the ECM?

Thanks,
Domenick

I'd try getting it to a place where they can read the codes. I suspect the link error is a problem between the reader and the car, not the car's fault.

Followup question, how long has the car sat since it has last ran?

You could try starting it, then pull a sparkplug, see if it looks either fouled or very dry.

You've been taking a good approach with the diagnosis, don't start throwing parts at it. Shotgun approach rarely works and the ammo is expensive as hell. Don't spend money on parts, spend it on diagnosis.

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I was running it every day up to about three weeks ago when it just stopped starting up.

I will pull a plug and see how it looks and double check if I am or am not getting any sparke.

Unfortunately there is no Indy that I trust locally. The closest is about 70 miles away in Gainsville Fl.(Continental Imports). The nearest dealer is in Orlando Fl about 50 miles away who I have had a bad experience with a few years ago over replacing a light bulb.

Thanks,
Domenick

I found the wiring diagram for the K 40 relay and ran some test on it. From what I can figure out the k9 portion of the relay is not activating as it should when I turn the key on. If this does not activate then it looks like the fuel pump relay will not activate.

I will give this some more thought and double check to see if I have any bad solder joints in that portion of the k40 relay.

Update. Maybe good news! I had my wife try starting the car while I pushed the contact on the k40k9 relay, the car started right up! I am not 100% sure now but I think that this may be the problem.

If I wasn't such a clutz soldering I would try resoldering the board. I may try it anyway. At this point I have nothing to lose, so I may try doing it before I buy a new one.