yeah i agree....glyn. i usually change my batteries every 3-4yrs. Better just to change ahead time to then be straded some where in the boonies.

I was telling my gf the same thing last month when her car turned 4 to change the battery as preventative maintence. Then a week later her car died. When she told me the symtoms i already knew it was a bad battery. Drove to her location with a new battery and i had her up and going in 10min.

 

Yup. Do it now.
I thought i was being smart when I had the alternator rebuilt back in May 08 to avoid doing it down the road. The 2nd 1/2 was to replace the battery as well, since so many people seem to have both fail at the same time.

But, I was trying to see how long it might last.
I kept checking it, and it was down to 400 CCA from 850 new, but still worked, so I figured what the heck.

Well, guess what, my alternator died 5 months after the rebuild, I had to pull it out, and return it the place that rebuilt it and they replaced the rotor. It cost them more to fix it than I paid them she told me.
(2 year warranty!)

It's a small family owned business in Sunnyvale, thats been there before 101 was even built. (There's photo's on the wall) I've used them many times in the past.
Anyway, I ended up having to drive there twice, the last 2 days, but it's all good once again.

But the moral is, likely that old battery was putting too much of a strain on the alternator and fried it.

I took the owner, Lachele, a bottle of wine and chew toy for the shop dog, she really appreciated it, since she's ended losing money on me and was really a good sport about the whole thing. (I only paid 125 for the rebuild and it came with a 2 year warranty).

By the way the company is PAECO or Pacific Auto Electric. I'd recommend them.

I've gotten pretty good at pulling the alternator now. I did it in like 1/2 hour each way.

And yes, I got a new battery. I priced them all over and ended up at Kragens, they sell Autolite batteries, so it's a known brand.
I had sworn off buying stuff like that from Kragens...but it's seems ok.
If you call ahead of time they give you an extra 10% off, so it less than 90 bucks out the door.

 

Hi,
I just read the thread and thought that here there might be a solution for my problem too. benz w203 c240 2001

I left the car for almost 3 months and when i tried to start it i found out that the battery wass worn out.
tried to jumpstart with an old benz of a friend of mine....
bought a "new" battery from a local seller (this is crucial)
the battery is a sealed one (no acid or water to add) 95AH 800A 12volt
my benz battery is 100AH 700A 12 volt.
the old guy at the shop told me that it should work fine.
Still nothing though. (the keys don't work, the ignition won't accept the key or let it turn)
I checked the fuses in the back...

After some hours without hope i make my last effort and the remote key worked, opened the car, got recognized from the ignition and started the engine.
Only few minutes later to setup windows/roof/esp and take it for a ride.
Next day nothing again.

Now
The seller is a small accessories shop in a small town.
No benz workshop for miles
Could the new battery i bought be faulty or incompatible or even low charged (in the years laying to be bought?)

I have no clue...just anxious about my benz.
please leave your thoughts

 

its probably your seat control modules going bad and draining your battery over night.

 

Yeah Mike - I can tolerate minor nonesence with a car but getting stuck when I least expect it is not on my agenda

 

Hey TemjinX2, thanks or the reply, but i don't think this is the problem.

The thing is that today came one guy from a local auto electrical service.
His point of view was "let's jumpstart it and bring it to the wokshop for further detailed analysis/diagnosis."

Nothing. He connected his battery but everything remained as it was.
No remote control, no entrance of the key in the ignition but still lights in the cockpit on, instrument cluster working.

He took his "wired lamp tester" and tried to test the fuses in the fuse boxes (in the engine compartment and in the rear boot)

His verdict...
"We 'll try tomorrow with the computer plugged"
I am bit anxious about the result.

Any thoughts?

 

if the battery is too far gone..you can't jump start it. You can try just buying a battery at autozone and see if it works. If it doesnt you can just return it for a refund.

if not...it might be the rear sam.

I would try the battery solution first..since its a lot cheaper then replace your sam.

 

Have to wait another day, grrr, the electrician guy told me that he can visit my car with the diagnostic machine tomorrow.

Anyway i told him about the fact that a battery worn off attached to the car prevents it from jumpstating. He replie that he uses special cables capable to bring enough power to revive a track.

Anyway
i cannot stay and wait. I think i 'll try again now with the fuses, i found a chart that might help me know what i am testing.

 

Weird stuff going on and i hate em!

Till now i wasn't able to open the boot or unlock the 4 doors centrally, from the button over the radio.

Then i noticed that if i was patient enough to hold my finger to the button for about 15sec i could open/close the doors.
Also the instrument cluster shows my correct km only for a moment after which reports "------------" till it turns off.
Turning on the radio, after a while (~20 sec) it automatically shows the message "PROD" and stops working.

I bet you can imagine the "paranoic" scene of me into a vehicle pressing any possible combination of buttons and holding em down for short time...(in combination with tuning on/off the front lights - alarm etc or remote control combination)

Results
1.For a moment the ignition recognized my key, i heard the sucking sound, an even turned it....but....damn
nothing happend i returned the key in 0 position and that moment of glory began a really obsession.

2.The radio now can play fo ever without stopping after a while with the "PROD" sign.

3. The instrument cluster now shows the correct total km.

4.The central lock/unlock works perfect.I just press the button and it opens/closes the doors.

Damn i don't know how i managed, but i believe that there is some kind of code going on...

I also foun out that when i use the remote control by pressing a button a red light frighs for a moment.
Now by pressin and holding 2 buttons at once after 10secs the red light flashes 2 times....

what does these things means..i don't know....yet

 

I think you either have a dud battery or an undercharged battery or a poor connection to the battery - Are you sure that what you call a sucking sound was not a fizzing sound which would indicate a bad connection at one of the battery terminals

 

Hi,
No the sound was from the key
as when it normally gets accepted in (recognized)

 

just spend 10min and swap out the battery. If you take your old battery to autozone they'll even tell you if the battery is no good or not.

It takes a lot more juice to crank the car then to run a radio or open doors. Cranking the car is actually when the car uses the most power. Anything after that doesn't use much in comparison.

If the car's throwing a code, just barrow a obdII reader and download the code.

You should try ruling out the simple problems first. If its more then the battery, the electrician probably can't help you anyways because more then likely it'll be the alternator or rear sam.

 

The thing is that i have already changed once the battery! Installed from the begining...

I 've even changed the bateries from the remote.

But please let me explain to you that the prolem is that
my key doesn't gets recognized by the car!
I mean i just insert the key and it acts as if i was inserting some others key (for example my brothers benz key)

The problem isn't the motor non starting up... it's the key..
i cannot turn it...it's blocked in position 0!
i cannot open/close doors with it.

If these 2 simple tasks need a lot of power then i guess you are right and they sold me an used battery or my "new" battery worn off over a night...

I just wonder if my key need some kind of sync as i ve read in other threads (for other benz models).
any clue?

 

+1 Mike - I would at least take the battery out of the equation by checking it

Neuro,
You say when you first changed the battery everything worked fine. Low voltage/low power can mess big time with modern electronics. A digital camera is a classic example. Batteries for a digital camera will frequently not reach threshold to even turn a digital camera on but you could run a battery radio with those same batteries for weeks.

You are taking it forgranted that it is a transmitter (IR & RF) problem (i.e. the key) It could equally be a receiver problem i.e. the car - due to low voltage.

Check the battery & get it behind us.

 

did you leave the key in the ignition when you swapped out the battery and reconnected it? If you reconnected the battery with the key in the ignition you could've blown out the rear sam.


taken from this thread

https://mbworld.org/forums/showthrea...hlight=key+bad



It could still be a bad battery if your seat control modules went bad and started draining your battery over night, either that or your ignition is going bad.

Only time when i couldn't crank the car...was when my seat modules drained the battery, but i could still open the door and turn on the radio. Then two days later the car completely died.

I still think its the battey since ignitions don't go bad often, you key doesn't need to be reprogrammed if it could already open and unlock the doors remotely. If the rear sam blew out you should be having worst electrical issues.

 

Glyn M Ruck

As i said before, as soon as i found out that my battery was dead:
1st i tried to jumpstart it....no success
2nd went to a local auto accessories seller to buy a new battery
no success again...
because i installed the battery and nothing happend (meaning that the remote was dead, no unlocking/locking, no entrance to the ignition, couldn't move the key...)
So i closed the car and went for a coffee with my friends, after some almost 5hours returned only to unplug the new battery (first i rechecked the remote, invain. I didn't want to consume the new battery because i thought i could return it for a refound...)
When i touched to unplug the negative pole i saw a spark and thought to try again, and it worked...
The remote was working fine and i started the car and took it for a ride.
Thought everything was ok so i slept over it.
Next morning, without touching anything....my remote was dead again.
please note
i have 2nd remote that also doesn't work..
I changed the batteries of the remote...

and pretty much everything i said before.

TemjinX2

No when i took the battery of the key was in my pocket, always because i need to test the opening/closing thing of the remote.

The electrician denies the fact that the problem is within the battery, because he tried his (trying to jumpstart the car) with no use.

Today i also tried my other car battery.
i unplugged my battery and connected the cables from my other car directly to the terminals of my benz.
I even tried by passing the cable for the negative pole(in some threads i read that sometimes is defective an creates problems).
No results...

Don't know...
Anxious about tommorow testing with the computer of the electrician guy.

 

If both remotes don't work it's not the remotes. It's the car - See what the electrician guy comes up with

 

The electrician come out with nothing...
I am not sure if he finally made the correct diagnosis as the problem of the
key not gettin accepted by the car i think prevented him from using correctly his diagnostic tool.
Anyway he said that probably the problem is withing the sistem Key-ignition, an that he was sory but i really have to bring the car to his workshop and then the might be able to do and tell more.

I checked the voltage of the batery is 12,4 almost.


If anyone have any other ideas, please feel free.

Ps no i cannot move the car because of it's parking position between tight walls.

 

Some other electrician visit the car and told me that the problem must
be within the ignition module...
I am still not sure! How come and my remote-keys don't work either for unlocking/locking the door? What is the connecion?

Tried the justanswer site with no great help...

Damn
Today i found and tried the number of the mercedes benz 24 hours assistance...
they simply won't pickup the call....Great i am really stuck....Damn

Now i am thinking of "sequestering" a mercedes benz technician from a town nearby and force him to check the.... hmmm....car.
To be honest i would really pay for this diagnosis/repair in loco...

 

What about the Key batteries?
Did you replace those yet?

 

Both key batteries are supposed to have been changed

 

Well here is my 2 cents. I had "undervoltage consumer defective" too. I did all sorts off tests.
1. measured voltage with car idling, I was getting 13.2, but after couple of minutes it slowly droppes down, I thougt it could the alternator

2. measured voltage with engine off, I was getting above 12 volts, and what I thing the "undervoltage consumer defective" shows up only when voltage drops below 12 volts.

3. next morning could not start the car, the cluster was lighting up but not enough juice to start the car, I got jumpers from other car (not running) cliped the other end to my battery, start the other car let it run for about 5 min, shut it off, remooved jumpers, nad my car CAME UP. Well it made me think the alternator was bad

4. the same day at work I asked my body to help me up, what I was going to do is touse jumpers from his battery to my end and disconnect my battery just to check the alternator. I have told him stories that you do not want to disconnect battery from Benzs at all, as it might give more books to read :}}}. Well I had to step off for a sec. my body was at my car, and guess what hapenned ...... he disconnected the battery.. %&*^#$$%#
The only good thing out of it was that the NEGATIVE CONNECTOR WAS LOOSE ON THE BATTERY

4. Anyway I had nothing to lose, I put connector back on jumped to his car, started his car, let it run for 5 min min, shut down his car, disconnect jumpers, start mine no problem, voltage was about 12.3, which I guess enough to get you start the engine. My next step was to disconnec the negative end from the battery again (my body did it once already anyway .^%&$%&^#@), and if the car is still running that it means the alternator is working, well I disconnecter the negative end from the battery and ..........
........ CAR IS STILL ON, turned on lights, A/C, everything was working with battery DISCONNECTED.

Well it proved me that it was defective battery, which easy DIY (make sure use have some sort of power to the car while doing it) and for some reason it was not charging off my alternator even though it was working. My guess it is because this car have to much brains in it, and it sensed something wrong with the battery and was not giving it juice anymore.

Now the second problem, since the battery got disconnected I have got a message something like that: " elec. stability prog. not availb. ESP " . I was reading other posts where you have to turn wheels all the way to the right and that to the left, drive a bit, and so on the last thing was to empty the ash tray (russian joke). But I was reading one post where the guy found burned out fuse (#62) which was the problem (he also disconnected his battery :}}} ). Well I looked for that fuse ( fuse box under the hood C240 2001 W203) but it was fine, that I was checking the other ones , they all seemed fine. Well the only problem I was thinking of was rear SAM box ( I guess the other name for the FUSE box), as many had problems with it while doing any type of electrical job on the car.

But I was removing fuses with the engine runing (I was not thinking about while doing it as I was pissed off with my body who got me ESP message), when I got back to the car there was 9 foults on display, I was F%%%%, turned off the engine , turned it back and miracle NO FAULTS AT ALL. I do not know what cleared it, but I think while the car was runnig and I was removing fuses ( all clear ones under the hood) and putting them back one at a time, something got reset. Drove it around the coner - no faults

I will attach fuse diagramm, I found it on other post, I am sorry I do no remember who posted it, so I am not claiminig that it is mine

 

Rich, did you ever happen to figure out what was causing the P0702 code to remain in the system even after a replacement battery, and a code clear. I fear my car is doing the same thing and I am at a loss..

 

Hello all,
I bought my first car in September 2020. It is a 2006 c230 sport. I have a problem with the car shifting out of 2 gear. I changed the coil packs and spark plugs, nothing changed. I proceeded to bring the car to a transmission shop where they scanned the car for free the owner tells me the code he got was p0702. I watched a few YouTube videos about the code and what I need to do to reset the 0702 code I got nowhere with it. I purchased a $150 car scan tool called MBII by iCarsoft, from the YouTube video I watched. I honestly can admit I didn't know what I was doing when trying to reset the code because the video I watched wasn't clear enough when it came to resetting the code. I've been doing some research, which stated that the problem could be as small as buying a new battery. I decided to leave the car alone until today. I randomly found a link that leads me to mbworld and another link that leads me to the c class thread. I am looking for some help from some experienced w203 car owners. Any help would be great. Thank you.

 

Welcome to the forum. I would advise you create a new thread within the W203 C Class Forum and explain your issues there. This way there will be more visibility on your issue. Also, you can use the search feature of the forum and search keywords within the forum for help with what your issue is.

Here is a thread from a member describing your issue:
https://mbworld.org/forums/c-class-w...ode-p0702.html