Car dies on me - needs towed - PeachParts Mercedes-Benz Forum

sokoloff · #1 04-19-2017, 06:12 PM

E300D - Picking up someone at the airport today. I pull into the terminal and am idling for no more than about fifteen seconds and the cars shuts down. Won't start again although it cranks just fine. No check engine light. It looks like the fuel lines are full. Half a tank of fuel and the first half of it went through the system just fine. So I had to have the car towed home about 45 miles.

When i get home the tow truck driver turns the key and the car fires right up. Seems just fine. Haven't had a chance to hook up my OBD scanner yet, but I'll do that tomorrow, if I don't find out anything else.

So what could it be and where do I start looking? Nothing like this has ever happened before. I'm stumped. First thought is to check both of the filters, but they certainly aren't due for replacement yet. Maybe a bad batch of fuel?

Side note - I went through several heavy downpours on the way to the airport, but never went through any water more than a couple of inches deep.

shertex · #2 04-19-2017, 06:45 PM

If the K40 has never been replaced I would replace it.

tyl604 · #3 04-19-2017, 06:48 PM

Does the diesel have a cps?

sokoloff · #4 04-19-2017, 06:51 PM

Thanks - never thought of the K40, but I've been carrying a new one around in my trunk for ten years. There's not a test for it is there? If it is working now and I replace it, how would I know if that was the issue?

Also crossed my mind that I got a bad batch of fuel or maybe I'm growing some penicillin in my tank, since the car gets rarely used these days - 3000 miles in the past year.

rasper · #5 04-19-2017, 07:10 PM

What's a K40?

R

sokoloff · #6 04-19-2017, 07:54 PM

This thread explains it pretty well.

E300 1997 stalls while running

shertex · #7 04-19-2017, 08:28 PM

Quote:

Originally Posted by sokoloff

Thanks - never thought of the K40, but I've been carrying a new one around in my trunk for ten years. There's not a test for it is there? If it is working now and I replace it, how would I know if that was the issue?

Also crossed my mind that I got a bad batch of fuel or maybe I'm growing some penicillin in my tank, since the car gets rarely used these days - 3000 miles in the past year.

From the reading that I've done, it doesn't sound like a bad K40 leaves any "smoking gun." Since you already have the replacement, it would be a good first step.

sokoloff · #8 04-19-2017, 08:37 PM

I'm leaning to swapping out the K40 too, but here's my questions. If in fact it stalls out on me again with the new K40, then I can be pretty sure that it wasn't the K40. I just went out to try to start the car and it started just fine twice. So do I chance that I'm okay or do I change out the K40 and have a better feeling that I'm okay? I'm thinking like Shertex suggests that since I'm not throwing any money away since I already have the K40 in hand, then that's the best and easy test to do and hope for the best.

sokoloff · #9 04-20-2017, 07:43 PM

Hooked up my code reader and got one code, P0725 which shows as the "Engine speed input circuit, module - transmission, Status - pending." Car starts up just fine. Didn't take it out to heat it up and worry about needing another tow. Glow plug comes on and goes off just like normal and there are no "Check Engine" lights showing. A little research seems to indicate that this code would be from a bad CPS as some of you indicated. I did not swap in my in stock K40, but I guess while I'm at it, I may as well pull it and see if anything obviously looks bad on it. Leaning to just getting a CPS and installing that. Is that an easy DIY job? Good idea you think?

sokoloff · #10 04-21-2017, 12:58 PM

Went at the job today. Didn't get very far. Disconnected the battery and removed the belly pans. Damned if I could find the CPS. Of course you can't see anything, even using mirrors where it is apparently located. Got to do it by feel. So I gave up and figured I'd take another look at the EPC and I'd ask you guys again. After reviewing the scans, it looks like I am looking in the right place, right at the base of the oil filter housing. I found one electrical connection that didn't look quite right, but I was basing that on what I saw from videos for the gas versions. So any of you who have done this job on the 210 E300, please share any tips you have. Is the job easier if the manifold is removed?

jay_bob · #11 04-21-2017, 03:57 PM

That P0725 code points to the input shaft rpm sensor in the conductor plate in the transmission, not the engine CPS sensor.

As others have noted, the CPS is not required for the OM606 to function.

I am still of the opinion that you have a classic K40 relay problem.
This is the module in the under hood fuse box that has all the fuses and relays in it.
You can replace it or try opening up your unit and touching up the connections with a soldering iron.

I think you may also have a conductor plate job in your near future. If you are comfortable and have the proper setup for doing a transmission service (dropping the pan and changing the fluid/filter) then the conductor plate can be easily replaced while you are in the transmission. I need to do this soon myself.

sokoloff · #12 04-21-2017, 04:12 PM

Thanks for the reply. Transmission was just serviced 5000 miles ago, so that's not due for a long time. Hoping that's not the issue. Here are two links that led me to thinking that it was definitely the CPS. These are pages I was sent out of the Mercedes workshop info. Scroll down to Code P0725 on the first link. It is #12. Hope these work. I also have a new K40 on hand that I was going to use until I read these. I would so much like to just replace the K40 and be done with it, because that is so much easier and cleaner. I hate to replace the wrong part and get stranded somewhere, so I'm trying to get it right the first time. Guess I pay for AAA - may as well use it.

STAR TekInfo

STAR TekInfo

jay_bob · #13 04-21-2017, 05:14 PM

Well I am wrong about the code being for the transmission sensor.
Usually P07xx is transmission related per the OBDII specs.

That L5/6 sensor looks at the ring gear, so it will be somewhere on the perimeter of the bell housing.

sokoloff · #14 04-21-2017, 06:52 PM

So Jay_bob, are you under the impression that the fault is with the CPS now? Would you even suggest that I swap out the K40 that I have on hand? My thought right now is to put in a new CPS only and see/hope that fixes it.

jay_bob · #15 04-21-2017, 07:16 PM

Based on the code and description in that manual (thanks for the link btw) I would focus on the sensor.

Sensor appears at 10:00 in this picture
http://www.w124performance.com/images/OM606_misc/OM606.962_engine/engine_04_rear.jpg

Right below the oil filter

Changing out the K40 can't hurt if you have a new one on hand.