DaveW68

The engines in the S550 are pretty much bulletproof too. The earlier MB developed 7 speed trannys had a couple of known issues, but outside of that, the powertrain components are very solid. Where German sedans really suffer, including Audi, is with their electronic components and software. They should really be farming that work out to Japan to develop, but instead they do it themselves, which they haven't mastered like the Japanese. Most issues with the these cars can be pinpointed to the electronics. MB may over engineer the bodies, engines, transmissions, safety, and electrical systems of their cars, but most of their problems have to do with their overly complicated electrical systems.

MB is almost always the first to develop new and important systems for cars. The W221 had several industry firsts, just like previous generations of S-class models. But then the Japanese reverse develop the systems for their cars and make them more reliable. Even American and Korean cars are now almost as reliable as the Japanese.

xpl0sive

Some reading material for you in case you decide to change the trans fluid yourself. I highly doubt the transmission would work after that, but hey you never know

https://mbworld.org/forums/c-class-w...ce-thread.html

a gread DIY from the "other" forum

http://www.benzworld.org/forums/w221...7g-tronic.html

mercedesbenzs55

Are you sure? The tranny change kit will be here this after noon.

I'm going to buy an infrared thermometer($11 at walmart), so no star needed for this.

superpop

You don't just change the tranny fluid on this car, well you can but the odds are high that it will do more damage than good. A good indy shop will do a tranny flush for around 400 bucks and they have the tools to do it. What you are failing to realize is that this is not a typical car that you can easily wrench on, Mercedes did not design this car for shade-tree mechanics, it is a very complex device that requires complex tools and knowledge to properly fix. You are trying to fix gunshot wounds with band-aids.

xpl0sive

good luck

a little quote for ya from an actual MB Tech who knows what he's talking about

alx

Sure you can. A cheap infrared thermometer is good enough for taking atf temp readings. I have done comparison out of pure curiosity and temps both taken by infrared and star were within couple degrees. You move around the bottom of the pan the the Ir termometer and you find the spot with the highest temp and you read there. The one thing to remember is that most ir thermometers are off so prior to using it you need to measure a known temp object and know your correction factor. Also the surface of what you read makes a difference. Thus apply a few strips of electric tape to create a black non- reflective uniform surface and point ir thermometer on it.

alx

At rest with accessories running you should be at 12.x Volts. Engine running you should be at 14.3-14.7 Volts. Your battery or charging system is suspect.

DaveW68

I admire Benzs55's drive to fix his car by himself. But he's finding out the hard way that he really needs to spend the money to have a professional diagnose and repair all of the issues. Everything he tries to fix, he makes worse or breaks more. It even seems that he messed up a simple battery swap by possibly touching the battery lead to the car body.

He needs to stop spending money on parts and equipment for his nearly dead 9 year old wreck and let a real mechanic with the right tools diagnose it so he can get a good idea on how much money it's going to take to make the car right. He can then decide whether it's worth spending the money to fix all of the broken issues, or dump it or part it out before diving into all of body and frame work.

I think spending $500 on a proper diagnosis would be money well spent before he breaks anything else trying to torque on it himself without the proper knowledge of how everything works. He's confusing this car with a 1970 Chevy.

MrRat

Ecu voltage looks way too low, but I lack experience with this platform. I would expect voltage to be approximately 14 volts when running, 12.6 volts or so when on battery power alone.

mercedesbenzs55

I had the voltometer hooked up wrong.

Front battery(starter battery):
Off:12v
On(with headlights on aswell):12.5-12.8v

Rear battery(Brand new accessory Batt.)
Off:10.54v(This is after a turning off the car and restrting it 20 seconds later)
On(with headlights):9.24v

Do I need a new alternator? This maybe what my Battery light means/Why my comand shuts off thinking the engine is off(goes into safe mode)/Why my speedo flickers when the engine struggles..

mercedesbenzs55

Dave, the issues with the MIL,ABS,battery light were there before the battery change. So lets take new issues after battery change out of the equation.

I am not selling this car. I'm not going to a pro to figure out if "its worth me keeping". I'll take it to a pro if need be to figure out what problems I have that I was not able to figure out.

I can figure these issues out with the help of MBworld members.

MrRat

That accessory battery needs to be charged or is defective.
Please note that the car is highly reliant on proper voltages. Once you sort that out you may find that it addresses most, if not all of your issues.

Just to be clear, the battery you just put in the trunk should be a fresh (Recent manf date) fully charged (12.8v or so) by an AGM charger. A non AGM charger can easily damage or fail to charge an AGM battery. Your car will not charge the accessory battery at 10.4V, it will just indicate a failed battery.

It is a bad idea to change the transmission fluid at this time. You would be adding another variable to your current issues. Sort out the voltage/ battery issue first. Then move on to the transmission fluid change once you've settled the electrical issue.

From a site about batteries:
Digital Voltmeters should read as the voltage is shown in this document. The sealed AGM and Gel-Cell battery voltage (full charged) will be slightly higher in the 12.8 to 12.9 ranges. If you have voltage readings in the 10.5 volts range on a charged battery, that typically indicates a shorted cell. - See more at: https://www.batterystuff.com/kb/arti....YJKY0cDF.dpuf

Abrown3mtg

Correct! Mb55, pull the front battery out of the car. Take it to any auto shop. They will test it for you for free. See if it is bad. Of so, replace it. I would highly suggest you not try and change the transmission fluid. At least not at this point. If you are mistaking gauges, hooking up volt meters backward, etc, I would not risk attempting a difficult and highly sensitive fluid change that WILL destroy a 7k dollar transmission if not done correctly. You are better off with 80k mile fluid in there than brand new fluid at the wrong capacity.

Steps:
1.) have the front/primary battery tested. I will give a 95% probability that it is your problem.
2.) Have the car scanned with a Benz computer,
3.) Off to the rack

nycphotography

Absent any evidence to support otherwise, this is absolutely correct in the short term.

Get the tranny serviced before you put any miles on the car... but only AFTER everything else is fixed.

superpop

This sounds like an issue with the muffler bearings. Have you checked those yet.

mercedesbenzs55

I haven't heard that one in years!

Ok, off to get a new battery.

Abrown3mtg

Take your old primary/front battery with you. Have it bench tested. You will also need it as a "core" which is kept by the auto shop. (Or you pay more). By testing it first, you can determine if it is in fact bad before sticking the new one back in.

alx

Front battery drives abs (initialization) and engine. Insufficient capacity will result in "engine will shut off in x minutes" messages, esp / abs errors and general issues.

WillieMack

xpl0sive

don't forget new blinker fluid while you're at it

Mike5215

Concur. Sometimes when you get an avalanche of errors from a bunch of unrelated systems it's because none of the control units are getting proper voltage and they start spitting out nonsense. Sometimes just a loose battery cable can cause it (which might be why it starts ok, but gets intermittently flakey on the road as the cable gets jostled.)

Quadcammer

mother of god, what is up with those voltages.

A battery at 10.x volts is absolutely dead.

Didn't you just buy this?

Also, if your voltage drops when its running, you likely have an alternator problem.

Like these gentlemen said though, proper voltage is absolutely key here. Don't do anything else until you have a good battery.

DaveW68

Oh boy!!

mercedesbenzs55

Costless auto parts didnt have it, I'm omw to MB of portland for the battery. $250 :o

DaveW68

Since you're going there any way, how about having it towed there instead and let them properly diagnose your car. Forum members trying to advise a guy with zero automotive knowledge likely isn't going to get your car running like a champ. You're always trying to think 5 steps ahead, but you don't even understand the original problem. I fear for yours and your family's safety regarding this project. I hope you don't burn your car and house to the ground because of your stubbornness to listen to logic.