E300D - need help - PeachParts Mercedes-Benz Forum

sokoloff · #1 05-04-2024, 01:55 AM

Yesterday I drove my 1999 E300D for the first time in two months - that's kind of typical for it. While driving I noticed that it seemed like there was no 4th gear. It would not shift out of third. At one point when I parked the car, it seemed like I had no reverse, but later the reverse worked. The car began to overheat, but turning on the heater helped that. The car never overheated into the danger zone. Then after a few stops and starts the "check engine light" came on and stayed on. I had the car towed home to be safe - that was about 50 miles.

I was planning on starting the two year service on the car, so when I got home I went ahead and began that service. I drained the engine oil and differential fluid. I also checked the transmission fluid level. Nothing seemed out of the ordinary. I did a cursory look at the engine compartment and nothing jumped out as being out of the ordinary.

I probably need to get the codes read, but I'm half afraid to drive it. So any ideas would be appreciated. This has really been a great car up until now.

dieselbenz1 · #2 05-04-2024, 12:53 PM

Well I'm thinking it's in your fuel system. Transmission not shifting cause engine is having difficulty and is low on power, you never noticed the power issue till it started overheating. But I don't really know??

sokoloff · #3 05-05-2024, 01:27 PM

I'm not sure if I'm having a senior moment here or not, but I thought I recall being able to use the climate control display to bring up fault codes? I know you can check various temps etc. using that display, but I thought there was a way to bring up fault codes from the check engine light. Am I remembering that right? If so, can someone give me the steps to pull up that info?

Benzadream · #4 05-05-2024, 02:26 PM

Greetings from another "senior" who's no stranger to those "moments", too. I have a '97 E300D with about 155k on the odo. Mine has also been a great car. However, I did have a few issues similar to yours earlier in my ownership. Once those were addressed its been good.
Unfortunately, the climate control display will only display data/values related to the climate control system. Still, a really GREAT feature and also an absolutely wonderful climate control system.
Re: Transmission problem. Has your trans fluid/filter ever been changed? I ask because MB claimed this car's transmission is "sealed for life" and never needs fluid or anything else...I guess? That sales pitch was a bunch of bs and that type of transmission hasn't been invented, yet imho. Not sure about your year, but mine didn't even have a trans dip stick! Had to buy one, not expensive and easy to find.
I'd start there, for sure. BTW, my "sealed for life" transmission fluid resembled used motor oil except it was dark green in color.
Another issue I was having was gear selection, like yours. The part needed was the "gear selector recognition control unit". About $100, easy to find (a bit of a pain to install). It lives in the gear shift selector and is what "lights up" when you put the shifter in the various detents (P R D 2 3, etc). The way to check its function is to make sure when you select a gear or neutral and even "park", that the selection is "lighted". Hard to see in sunlight, much easier at night.
I originally thought those were illuminated only to see them at night. That is incorrect.
Look up the part and you'll see what it does. It's actually part of the auto trans shift logic.
I'll stop there, for now, and wait to hear back from you. This little bit of maint/trouble shooting could go on and on.....
In closing, when was the last time your coolant and thermostat were changed?

sokoloff · #5 05-05-2024, 04:17 PM

Interesting info - thanks. I don't recall ever seeing that this transmission was "sealed for life." I also don't see a transmission service being listed on the service sheet. Anyway I've serviced the transmission a few times, the last one being in 2016, i.e. 20,000 miles ago. That means fluid, filer, torque converter and gasket. I had a note to myself to do it again in 2025 or 2026. That could change depending of where this all goes.
That "gear selector" issue you had is interesting. I'll have to look at mine, but I think the gears were lit up like they were supposed to be.
Coolant done in 2020 (7000 miles ago) using a five year coolant, so that's on tap for 2025 or 2026 too.
Keep those suggestions coming. I've got to figure out how/where to get a fault code read without driving the car very far.

engatwork · #6 05-05-2024, 04:51 PM

Is the serpentine belt tight and in place? I think you have a couple different issues going on. The port to read the code is in fuse box under hood. Look for a round port with a couple indexing tabs and you have found it. It may have plastic screw cover on it.

Was the tranny fluid level prior to starting maintenance? How about coolant level?

sokoloff · #7 05-05-2024, 06:19 PM

A quick look at the serpentine belt when this first happened didn't seem to be a problem. It was moving. But I will look closer since a year ago I had to replace the alternator and of course that involved messing with the belt.
Tranny fluid level was good when I checked it after the problem occurred. Coolant level was checked a couple of weeks ago and the level was good and it tested and looked good.
I now vaguely remember the location of the test port. Thanks for the reminder.

engatwork · #8 05-06-2024, 07:58 AM

Make sure the spring is not broken that puts tension on the belt. I've seen this spring break and you could still operate and drive the car, just not real aggressively.

sokoloff · #9 05-06-2024, 12:43 PM

Bit of an update. Right after I got towed home a few days ago I started my 2 year service and drained the oil and the car sat for a few days with no oil, so I couldn't start it up. Today I finished up with the oil change and started the car up. It started nicely and all the gears clicked into place, although I never took the car out of the garage yet. That will likely be my next step.
But I checked a few things. The lights on the shift lever did not light up and I thought "Aha, I have found the problem" as suggested above. Then I thought that maybe those selector lights do not light up in the daytime. So I turned my headlights on and the lights on the gear selector all worked like they should. I did not even realize that those lights don't light up unless the headlights are on. On my other cars those lights light up with the headlights on or not.
Checked the tension on the belt and it is nice and tight.
Coolant level was okay.
So my next steps will be a drive around the block to see if anything has changed Then if that works out okay, I'll make a run to one of the McParts Auto stores to get the codes read. BTW the check engine light is still on. Depending on what the codes tell me, I may have to buy my own unit specifically designed to read the Mercedes codes.

engatwork · #10 05-06-2024, 05:55 PM

Will be interesting to hear what you get when you "get it read".

To read all of the cars codes they will need to read via port under hood.

sokoloff · #11 05-07-2024, 12:06 AM

Do you know if any of the McParts stores that offer to read the codes do the reading via the port under the hood?

engatwork · #12 05-07-2024, 07:41 AM

I don't know.

Diesel911 · #13 05-07-2024, 08:27 AM

Quote:

Originally Posted by sokoloff

Do you know if any of the McParts stores that offer to read the codes do the reading via the port under the hood?

At Autozone about a month ago they gave me the code reader and said I could use it in the parking lot and bring it back in to for them to look what the code was. What they handed me had a GM only OBII connector on it. In my case it was a 2012 Chevy Equinox.

Did they have a Mercedes connector? I don't know.

Benzadream · #14 05-07-2024, 12:00 PM

Chances are "McParts Auto" won't have the connector you need. They usually only have a basic OBDII code reader/connector.
You probably don't want the inexperienced counter person anywhere near that 38 pin, under hood connector, anyway.
You can purchase just the adapter which connects the 38 pin to a standard OBDII scanner, like this one...

https://www.ebay.com/itm/285740247206

Of course, there are plenty of other options, as well.

engatwork · #15 05-07-2024, 02:30 PM

Good point about not allowing counter person no where near the 38 pin connector.