2002 C240 Not Displaying Any Codes

First of all, welcome to the insanity. Pull up a keyboard, and enjoy the ride.

I think you may have a poor connection somewhere. In my experience, one thin g is wrong, and causing many symptoms. What 1 item is common to all of the issues you had? 1) The frame of the car. 2) The battery. 3) The battery and ground cables. 4) The connector on the ECM (car's main computer). 5) The bulkhead connector where the majority of the wires pass through the firewall. 6) The ground wires from the ECM. 7) The ground wires between the display and the battery ground. 8) The display itself.

This may sound intimidating, but not if you test each item separately and then rule it out.

Now I have some questions for you. 1) Are the display lights giving false signals constantly, or only once and a while? 2) What has changed since the car was working correctly? Are you handy enough to do simple testing, or do you have someone that can and will help you through this?

Thanks a million for your response. Now for the answers (as best as I can respond) to your questions:

1. As of late, the signals are happening constantly

2. I got the oil changed at the Mercedes dealership

3. I do have someone that can help with the testing

Bobc's advice is good, I think I would start by checking the panel & ECU earths.

Another thing always worth doing is finding an online Merc. users forum, someone has probably had the problem before you & will point you to the faulty area.

Thank you for your response!!!

Hi,

Welcome.

I agree with Bob mostly.

I'm curios about the diagnosis of the 'faulty' alternator. Did they show you it was faulty?

I've had not exactly this type of fault, but close, when an alternator regulator 'lost it' and was putting out 16.5 volts. First fault I noticed was the radio quit. I slowed the car, dropping the motor speed and thus the output voltage, and the radio started up again.

Designed - in safety factor against over voltage.

Then I began to smell an acrid burning. "What the hell?"

The ECU started to act up. All the while the "Odyssey" battery was being fried.

Wasn't game to turn off the engine in case I couldn't get it to start again. Went to a battery shop. New battery (ordinary type) $180. New alternator $ 380. Shot-down Odyssey $600. Turns out that to replace the regulator in the alt. would have cost me just as much as the new alt. The whole thing was fitted by me in the car park in about 20 minutes.

And the jouney was doing a 'favour' for a friend???????

Just an example of the strange happenings a duff alternator can produce, although your problem does smack to me of a bad earthing problem. Have the engine to frame grounding straps checked (loosen the bolts/nuts, clean the interface and re-tighten with some lube from WD40 or sim). Cars which operate near the Coast are more prone to this type of fault. Where are you?

Be wary of those who will take your money trading on your mechanical ignorance.

And don't fall for the 'second opinion' ruse I had to pull on a 'difficult' customer:

"You want a second opinion? Listen very carefully and I'll tell you again".

Cheers,

Keep us up to speed with what you are doing. There is a wealth of knowledge here with the guys and gals, and we don't want to see you get hurt.

Stu.

Thank you!!!!

Thanks for the comment. Don't agree too much with me, or they will charge you with being an accomplice.

"Have the engine to frame grounding straps checked (loosen the bolts/nuts, clean the interface and re-tighten with some lube from WD40 or sim)." This is an excellent method of making a good ground, for testing, I will just use a jumper wire between a known quality power source (battery) to the suspected location. Sometimes for long runs on larger trucks, I will use a pair of adaptors I made up that plug into a 115 volt extension cord on both ends. The adaptors join the 3 wires together, and attach to a single spring clamp. If this changes the performance, then I would go back and do as you mentioned.

We'll do.

Hi! TG,

Did you eventually get someone to come to grips with the problem with the little Benz?

Keen to know how you fared.

Cheers,

Stu.