Im experiencing a few confusing issues in my 04 w203 c240. Today, with no prior electrical trouble, the engine would not start but all of the electronics worked. one hour prior to this I was driving it fine. On the screen below the gauges it said one malfunction, and " BRAKE FLUID! SEE WORKSHOP". this is after i re jumped it and let it run for an hour as well as driving for half hour. This brake fluid warning would disappear when I drove it, only appeared when electrical trouble happened. Duly, I am 2200k miles past my service B, idk of this affects or triggers anything in the car. Any idea on what the issue is? Thanks!

 

The brake fluid message likely means that you're low on brake fluid. That happens because as the brakes wear, the pistons move in more to keep "near zero" distance between the pas and the rotor. When the brakes were done previously, the brake fluid may not have been topped off afterwards - like it should've been. So, it is "possible" for a properly working brake system to show a low fluid level - from previously incorrect service.


As for the no start, does the starter turn? If not, it sounds like a vehicle security issue.

When did you jump the car, verses the no start condition? Very few people jump start a car properly.

 

RedGray, could you please tell us the proper procedure to jump start? I now have a 38000 mAh power bank emergency jump starter. Is it safe to use with our cars?

 

Duly, I forgot to note that today I got in the car to try starting it and there was no brake fluid warning. I checked the reservoir under the hood and it was about exactly middle way between min and max. the brake fluid warning came on only when I turned the key and held it for a second, then appeared. As far as the engine turning, there are no Pistons trying to fire or engine movement. It will only make a clicking noise and the lights will flash in the car (reading light, radio etc) and that's it. The only time it showed any life on its own was after the second time I jumped it and picked up dinner, it started to turn very weakly for one key turn after i turned off the car. Also please tell us how to jump a car properly!

 

Also to answer last part of your question, I was driving the car all day. Then after sitting for an hour I went to drive it again and it was dead. I got it jump started, drove to pick up dinner, it died again. I got it jump started a second time, left it running at home for an hour or two as well as driving it for 30 minutes more and then it still died again when I tried to start it later that night

 

The proper way and 100% safe way to jump start any car built after 1970 is simple.

********
i) Charge up the weak-battery for 5-10-15-30mins (depends on how low the weak-battery is).

ii) Fully disconnect your charging device/method.

iii) Start the car.


********



To go more in depth.....

There are three general ways to jump start a car.
1) From another car with a good battery.
2) From an AC charger.
3) From a mini-battery pack.

There are also 3 risk amount when jump starting a car:
a) The 100% correct and safe way.
b) The risky way.
c) The very risky way. :-P


Let's start with:
1) Jump starting a car from another car with a good battery.
In general:
Avoid connecting the jumper cables right to the battery.
Use the positive jumper terminal that most newer cars have.
Connect the ground to a good ground location. This can be harder to find.

1a) The 100% safe way:
With both cars off, connect the cars with battery cables. Use the jumper cable connection point on each car.
Start up the car with the good battery.
Charge up the weak-battery for 5-10-15-30mins.
Turn off the car with the good battery.
Fully disconnect the cables.
Start up the car with the weak battery.



1b) The risky way: (1A didn't work - the weak -battery is too weak, you need to get to the hospital for a surgery, an interview, a final test, etc).
With both cars off, connect the cars with battery cables. Use the jumper cable connection point on each car.
Start up the car with the good battery.
Charge up the weak-battery for 5-10-15-30mins.
Turn off the car with the good battery!!
Keep the cables connecting the two cars
Start up the car with the weak battery.
Fully disconnect the cables.
*** This results in the alternator of the weak-battery car trying to charge two batteries, and with the 2nd battery connected through a "higher resistance wire".
This puts a HUGE load on the alternator of the weak-battery car. That excessive load and then the immediate disconnecting of the 2nd battery can ruin/damage many voltage regulators.
Often, the damage is "latent", and the alternator will work for a while. Eventually, the damaged junctions inside the regulator fail, resulting in a bad alternator.


1c) The HIGH risk way: Do not do this!
With both cars off, connect the cars with battery cables. Use the jumper cable connection point on each car.
Start up the car with the good battery.
Charge up the weak-battery for 5-10-15-30mins.
Keep the car with the good battery running - VERY BAD!!
Keep the cables connecting the two cars.
Start up the car with the weak battery.
Fully disconnect the cables.
*** This results in the two alternators fighting each other. One or both may loose the fight.

 

Next. :-)
2) Jump starting a car from from an AC charger.
In general:
Avoid connecting the jumper cables right to the battery.
Use the positive jumper terminal that most newer cars have.
Connect the ground to a good ground location. This can be harder to find.

1a) The 100% safe way:
With the car off, connect the AC battery charger. Use the jumper cable connection point on each car.
Charge up the weak-battery for 5-10-15-30mins.
Turn off the AC battery charger.
Fully disconnect the charging cables.
Start up the car with the weak battery.



1b) The risky way:
With the car off, connect the AC battery charger. Use the jumper cable connection point on each car.
Charge up the weak-battery for 5-10-15-30mins.
Keep the AC battery charger on.
Start up the car with the weak battery.
Turn the the AC battery charger off.
Fully disconnect the cables.
*** This results in the alternator of the car fighting against the AC battery charger for "some period of time". Some professional battery chargers are "designed to handle this method of starting".
Imho, do not trust it. Especially if you're a dealer service only person. For my C230, that's ~$1,000 for the alternator, and ~3hours of labor at ~$200/hr.
Imho, if 1A didn't work, get a new battery!

Depending on the battery charger, the alternator may have get stressed a little or a lot. This method also adds risk of damage to both the alternator and the battery charger.

 

Next, :-)
3) Jump starting a car from a mini-battery pack.
In general:
Avoid connecting the jumper cables right to the battery.
Use the positive jumper terminal that most newer cars have.
Connect the ground to a good ground location. This can be harder to find.

3a) The 100% safe way:
With the car off, connect the mini-battery pack's cables to the car. Use the jumper cable connection point on each car.
Charge up the weak-battery for 5-10-15-30mins.
Fully disconnect the cables from the mini-battery pack.
Start up the car with the weak battery.



1b) The risky way:
With the car off, connect the mini-battery pack's cables to the car. Use the jumper cable connection point on each car.
Charge up the weak-battery for 5-10-15-30mins.
Keep the cables from the mini-battery pack connected.
Start up the car with the weak battery.

*** This results in the alternator of the weak-battery car trying to charge two batteries, and with the 2nd battery connected through a "higher resistance wire".
This puts a huge load on the alternator of the weak-battery car. That excessive load and then the immediate disconnecting of the 2nd battery can ruin/damage many voltage regulators.
This can also damage the mini-battery pack, since many are not designed to be charged by a high-current (100+ amps!).

 

Besides a bad alternator, or bad battery, it could also be a bad battery cable or connection.
There are cheap voltage monitors that plug right into the cigarette lighter. Don't leave them plugged in all the time.
They are an easy way to check the voltage of the battery before you start the car, and with the car running.

Walmart, auto stores, Amazon all carry them.
An example is: ~$10
INNOVA 3721 Battery and Charging System Monitor