I have 2 keys for my 1998 C230 and they both dont work (one has dead batteries)
The 1 with the good batteries does lock/unlock the doors fine but I understand that the EIS inductively activates the chip in the key whereby sending out its code to authorize its use, so the batteries have no play in the EIS function

The cars starter battery had been dead for about 4 months so I am not sure it if has caused any programming to be lost.

But before I go spending big $$$ on a new key and re-programming.
I want to eliminate what might be an electrical issue with the Brake light circuit that might be the root of the cause.

SO the Basic question is: Do the Brake lights on a C230 light up when the brake pedal is depressed without key in the EIS and turned into a position?

As I believe the brake circuit needs to be energized for the EIS to function,
and since my Brake lights don't come on when the pedal is pressed, I feel this might be the cause of the problem. (I electrically and visually checked the Brake Light fuse and its good)

But if it is normal for the brake lights Not to light without the Key turned into position the problem is deeper than that.

What is Normal?
Thanks for your Help.

I don't think the brake lights on my W203 C240 come on with the ignition off....if the brake light switch is the same one used in the W210 e-class, they are known to fail/have issues. Thankfully its only a $40 part.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

the info you've provided is a bit sketchy. you dont' want to be chasing ghosts (secondary indicators) when you've not isolated and verified the cause yet. what is the voltage of the car battery, at rest as well as under load?

__________________
-- raymond~
47º 34'N 122º 18'W

Both keys failing at the same time is highly unlikely. As raymond says the battery could be the problem. If the voltage is too low (<12v) the ECU won't perform the starting process.

FYI - The brake switch is more like $20 (OE) and almost anyone can install it themselves using DIY instructions online.

__________________
Good luck.






1998 E320 Wagon

Let me get those voltage numbers and I'll post them.
Yes, plenty of ghosts to chase on this project.
But I guess an easy question to nullify the brake circuit issue is to know if a C230 can be started without depressing the brake pedal ?
If it can, then the brake engagement issue is not in the equation.

You are chasing your tail. Brake lights wont prevent starting. This model has several systems networked together that work in unison to recognize the key, release DAS, and start the car. Your most logical next step is to pay someone competent at daignosing multi-network systems to sort the problem. You will total the car before you fix it by throwing parts at it.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

My voltage fresh of the charger at about 75% done non-loaded was 12.70, when loaded into the car and with the trunk light illuminated was running at 12.51.
still no turning of the key.
I checked the brake switch and noticed, there are 2 connections, 1 that is normally open but closed when pedal depressed, this has 2 larger heavy duty standard MB type of cylindrical pins ( but 3 wires) to it and the 2nd has a typical small blade type of connection 2 wires and is closed when the pedal it depressed or not. seems like it might be malfunctioning.
I dont have a wiring diagram to determine what its correct function should be
Yes Dux, I dont want this to be a money-pit fix, and the cost of a tow and Diagnostics may cost more than just the maybe 1 part needed ~ I guess~

FryBird, to the best of my knowledge the brake lights of any MB vehicle will not function unless the key is in the ignition and at least turned to Position 1 (See your Owner's Manual for explanation if you don't understand). The engine will start without the brake pedal being depressed; however, the brake pedal needs to be depressed to shift from Park into gear ... a safety feature.

__________________
Fred Hoelzle

How good is the multimeter used to check the battery? Fully charged battery should read over 13v.

__________________
Good luck.






1998 E320 Wagon

It's a quality Sears Craftsman heavy duty meter, but as I mentioned it was only at about 75% charge. The P.O. Said the MB dealer would try fix by selling him a brand new key and reprogram the ECU, EIS, ESL all to match at a cost $2000~$2500 ( maui prices much higher than mainland )
I'm thinking/hoping 1 component like the motor on the ESL has gone kaput and a less expensive option to the dealership mega cost can resolve the issue

cheap wild idea. trickle charge battery to reasonably full state.

place key in ignition and walk away. cook dinner...leave it overnight if you have
the car in your garage. report back

p.s. you said the key "doesn't work" which gives folks an idea but
it is lacking detail. step-by-step, what do you do and what sounds
does the ignition make (or does not)?

__________________
-- raymond~
47º 34'N 122º 18'W

Insert smartkey fob into key receptical (EIS) on dash and the key fob does not turn clockwise to turn to the accessories position so it won't turn further to start the engine .

Does it unlock the steering wheel when you insert the fob? 12.5 sounds weak for a freshly charged battery....usually mine are all around 12.7+ even after sitting.....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

No pawoSD it doesnt turn at all, Very similar to this video on the link shown below at the bottom.
*NOTE* on this video you hear an (unlocking?) sound when the key is inserted and another sound when the key is removed.

with my car there is No Sound at all. and it wont turn after multiple attempts

I think it is the Electronic Steering Lock motor that is heard in the video?

can anybody confirm
Thank you.

1998 C230 Key Problem - YouTube

If there is no sound at all then I suspect the key(s) are no longer authorized to the car. Might need to re-program them.

The zip sound when inserting or removing the fob is the steering lock solenoid.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)