1999 E300D Electrical Problems - PeachParts Mercedes-Benz Forum

searaypaul · #1 04-26-2002, 01:25 PM

For those of you who have been here awhile I have posted several unusual problems over the last two years. Most of them electrical. The dealer has replaced electrical motors and thermostats, complete A/C system, and been unable to find a nagging transmission problem and check engine light problem.

A friend recommended a local independent MB mechanic. I took the car in and told him my tale of woe. He states all of the sensors are good, he does not believe the electric motors were bad and I agree, the a/c should not have broken, and the check engine light should not be on. He ran the codes and got numerous faults, much too long to list, he checked the wiring harness and sensors and proclaimed it good. He went to the computer and said it is throwing out unusual readings and wants to replace it with a rebuild. What do ya'll think? I would be thrilled if this fixes my troubles. I have suspected the computer or harness for awhile. The mechanic states this is a known problem. Thanks for your replies Car has 72000 miles on it.

#2 04-26-2002, 08:58 PM

Isn't the car still under some type of warranty? How much does he want for the rebuilt computer job?

searaypaul · #3 04-27-2002, 12:02 PM

The car is out of warrenty. A/C broke at 51K and I was on the hook for most of that repair OUCH. As for the price I will find out Monday.

#4 04-28-2002, 03:52 AM

Multiple fault codes usually results from some sort of system wide problem--such as a faulty harness, faulty ECU, or perhaps a power surge from a faulty alternator.

I'd reseat the ECU connector, as well as some of the connectors under the hood. Inspect the terminals in the connectors for any signs of "backing out"... if you know all connections are good, it's either the ECU or harness.

Verify charging system performance too--should be a steady voltage regardless of engine RPM, and it shouldn't exceed about 14.4 volts.

-Joe

searaypaul · #5 04-29-2002, 11:07 PM

Thanks for your reply. This makes me feel better about the bill I am sure to recieve. I will question the fellow about voltage spikes as I recall many electrical problems in this forum were caused by faulty alternators and weak batteries.

Have a great day

Paul Cleary

searaypaul · #6 05-07-2002, 11:06 PM

For anyone who is intersted: I got my car back yesterday after ten days. I am very optimistic that my problems are over. The car seems to perform completely different than before, I probably just missed it.

The transmission is shifting much smoother and even though it is warm in SC I can tell a distinict difference from what it is used to do when cold, see another post of mine. Bad seal, may yet be true as the problem was worst when cold.

The heating and cooling system actually switched over from A/C to heat last night in order to maintain the cabin temp. The car had never done that before without a little help from me: ie bump the the temp control Auto button. Replaced control head twice and thermostat six times

The turbo winds up much quicker than before. Used to be more lag time when you needed power. Unable to duplicate

The radio has stopped doing anoying things, changing volumne and switching stations. CD player caused these problems

So far I have gotten the key back every time I turned the car off with out a fight. Take foot off the brake and put car in park before shutting off.

The engine temp is not flucuating as much. Normal.

The idiot lights on the dash have gone out. Reset computer

The independent mechanic replaced the electronic control unit and then drove it for 250 miles, with my permission, over the weekend. If this takes care of my irritations I will be thrilled. Too bad MB could not find the problem while the car was under warrenty. I am now collecting donations to pay the Mastercard bill next month.

Have a great day

Paul Cleary

1999 E300DT 73000 miles

#7 05-08-2002, 02:32 AM

Glad your nightmare is over. Try not to worry about your bill, that beautiful piece of diesel german engineering is worth it!

shoe · #8 05-08-2002, 11:45 PM

Is this typical of the late 90's E Class? I was thinking of finding and buying one and did not want to get into an exspensive or chronic repair situation. I am thinking 96 to 99. Hopefully diesel, but they are really hard to find in south Louisiana. I have seen quite a few gas burners, but the 300D turboI have now keeps me wanting to stay with German diesels. I would like as many comments from the experienced and those familiar with these year models. thanks ahead of time

searaypaul · #9 05-10-2002, 09:47 AM

What is being missed here is that any car can have a problem. Todays vehicals are so complex and have so many electrical componets that you need to find a GOOD mechanic to service them.

My car was giving the mechanic symptoms from day one and the mechanics were treating the symptoms and not curing the problem. I equate this to going to a doctor and complaining of pain in your arm. The MD then gives you a pain pill but fails to realize you have a compound facture which is the source of your pain and your arm continues to hurt.

Anyway I have driven my car another 500 miles without any problems and I am going on a short trip with it this weekend. I am very happy now as all of my troubles have gone away for now. Benzmac and the rest of the mechanics on this site will appreciate this. I am going to get the mechanic his lunch today because I think finally he found my problem.

Have a great day

Paul Cleary

shoe · #10 05-10-2002, 04:21 PM

Yes, I am well aware that any vehicle can and does have problems. However, some models can an unusual number of problems. That is what I was looking to find out. Eg, the trap oxider on the mid 80's diesel's ect. I will buy one regardless, I just wanted to know if anyone considered any particular year between 1995 and 1999 to be better than another. After all, if it is made by man it will break at some point.

JimSmith · #11 05-10-2002, 05:37 PM

shoe,

I did a review of the differences when I got my 1998 E300D TurboDiesel. In a nutshell, all the Diesel W210 E Class cars have about the same body, interiour and accessories. So you end up picking the car out based on price and performance. In that scenario, a 1997 or earlier car will cost quite a bit less, but it will also not perform like the 1998 and 1999 TurboDiesel. I got hooked and bought the higher performing car and sofar it has been great. I had some issues with the front seats making snapping noises at the transition of accelerating or braking and they have been eliminated by warranty repairs. I also bought a Starmarked car and have an extended warranty through that program.

The later cars also come with the remote door locking feature and the new wierd key that is not a key but a little computer interface. So far I think the car is great. I get worried when I read about the less than robust climate control system and the other electronic stuff. I figure if I keep it for the next twenty years I will learn a lot more about those things as it becomes necessary.

I get 30 to 33 mpg, depending on how often I check the accelerating ability. Since it is really hard to believe a Diesel can perform like this, I do it a lot more than I need to....so others with a lighter right foot might get better mileage.

Your assessment that you will always encounter some failures is correct. What they might be, compared to what know them to be on the older models gives us some concern as it forces us to learn new things to maintain the cars ourselves. I think that goes by the name "progress" in some places, and we all know you can't stop progress. Good luck with your choice, I don't really think you can go wrong. Jim

shoe · #12 05-10-2002, 05:52 PM

Now that is type of informatiion I am looking for. Thanks, Jim, I fell in love with the current E Class when Mercedes went to it in I think 1995. I have always wondered what the differences were in year models, as the body changed very little. You may be correct on the effects of the right foot on fuel milage. I spoke to a gentleman about a year ago, I beleive he had a 97 or 98 model E300D and he indicatted that he got close to 40 MPG!. I too, plan to get a starmark vehicle, I just need to wait a little while longer to get the Harley paid off. I like to start early in my research so I can get as much for my money as I can. Again, thanks for the input.