W203AL

Hello,

I have a problem with my mercedes.

The car is a W203 2004 automatic 220cdi.

For the past month more than in 1 occasion I cant start the car.

When i insert the key i hear the ELV, then i open the ignition to position II i hear a "bzzzz" from the engine bay , when i try to start the car nothing happens at all! I switch the key to position III and it's dead,, no response at all!

The battery is brand new (i replaced it thinking it was the battery). When i turn the key to position II i see that the panel gives me random errors like ESP not working and Coolant System not working... then 2 out of 3 times that i tried the car would start if connected to the battery of another running car... while another time it just started without me doing anything... and whenever i manage to start it all the error codes are gonne and the car is 100% fine...

This is making my car unreliable and i cant drive out of town as i fear i will get stuck somewhere if i turn off the car ((

HELP ((

Glyn M Ruck

Check that fuse 52 is not corroded & replace 15A with 20 amp. Also check 31 & 57. I think they still apply on a diesel.

Check the starter relay
Check the starter motor
You could have an EIS that is failing.

W203AL

Hi,

Thank you for your answer. I checked the fuse52 and the fuse is 25A. Should i change it with 20A??? All the fuses you mention are not corroded and seem fine.

If it is a starter motor fault, why would it give the error messages about ESP or Water Coolant in the panel? Does that happen when the motor starter is faulty?

Another issue that happens sometimes is that i have a hard time with locking and unlocking the car from a distance. Checked the key at a key specialist and the key itself is fine. When it happens i need to be like 1inch away from the driver's door to lock and unlock the car.

I was told that it might be the front fuse and relay box. Is it safe to have it removed and checked if everything looks fine on the inside of the fuse and relay box? Do you think that can be an issue that gives this sort of problems?

Sorry for the long message but this issue is really upsetting and i am really trying to figure out what is happening with my car...

Thank you for your help!

Glyn M Ruck

If fuse 52 is already 25 AMP leave it alone. That makes sense. The diesel cars have an uprated starter motor. Gasoline cars came with a 15 amp fuse & Benz put out a bulletin to raise it to 20 A. Blown fuse 52 is the most common cause of a no crank condition.

The locking/unlocking from a distance is dependent on the RF circuit via the rear screen antenna operating properly & the key battery & transmitter condition. Once you put the key in the EIS it is inductively energised & does not depend on it's battery for the handshake. Close up you are depending on IR transmission via the drivers door handle sensor. Have you by any chance had a tint fitted to your windows?

The problem could be the front SAM but it is unlikely. It sounds like a failing EIS which is expensive. It could also be a CANBus issue or short.

Please get hold of an OBDII scanner & read stored codes & post them. The OBD Port is under the steering column under a rectangular cover.

See the handshake process from key to EIS in the Wiki so you understand what is going on & the start enable process.

If you can't give us stored codes I'm afraid you need to have the car properly diagnosed with a Star DAS at a dealer. Without guidance of the stored codes it is guesswork & you have multiple trouble conditions.

W203AL

Hi again,

Thank you for the very long reply and for taking the time to help me out

I had it diagnosed with STAR and most of the times the computer says it can't connect with the EZS ... then without doing anything... it manages to connect after a few trials and the only errors and faults i get are the Radio (which doesnt work because it has gone in safe mode because of disconnecting the battery) and an air conditioner issue.

All the other errors that appear in the panel when the car doesn't start are not there anymore (in the panel and in the Star test).

So when it does connect to the EZS it actually shows no relevant faults connected to this issue...

Regarding the key i had it checked at a electronic key specialist and he said the key is fine... its either the sensor or the program (according to him) but this is not sth that bothers me that much... the big trouble is the starting/not starting issue...

Once again thank you for your time and looking forward to your thoughts after the info above...

W203AL

Hello again,

I was told today that it can be the front fuse box... they want to remove it and check it for problems... is this a possible option ? Is it safe to remove it and check it for problems?

Thanks

Alswag

It could be the front SAM. Usually if there's multiple issues (electronic related, as well), I like to blame the front or rear SAM modules as they tent to **** the bed once in a while. It wouldn't hurt to test it.

Glyn M Ruck

Let them check the SAM & reflash it. Otherwise you are going to have to methodically go through everything remembering that the EIS is the top of the control pyramid. You also need to check the CANBus for potential shorts. A real bugger if the car is not communicating properly with a Star.

W203AL

Thanks for your patience and the suggestions ... I will start with the front SAM and if that shows no signs of faults i will check the motor starter as well... i guess the only thing i can do at this point is eliminating possible options one by one... EIS is in my list as well but im really hoping its not the EIS as i know it can get really expensive... i will update the thread in case someone else is interested regarding the same issue... ... please keep your suggestions coming in case something else comes to your mind... thanks a lot

W203AL

the good news is that when it does communicate with STAR it shows no faults at all and everything seems in place... the bad news is that it communicates properly with STAR when it feels like it... which lead the guys who checked it to the Front SAM ... thats why they want to check that first... ill have a go at this option and see what happens...

Glyn M Ruck

I don't believe it is communicating properly with the Star as it obviously does have faults.

Good luck!

While they are messing around with the front Signal Aquisition Module tell them to check the starter relay in cavity S

W203AL

Will replacing the SAM with a new/used one from another car need reprogramming of any sort?

I changed the solenoid on the motor starter and cleaned the motor starter itself but it still keeps happening... now i am left with the option of messing around with the front SAM but i am not sure whether i should have anything in mind before doing that?

I was told i need to check the solder joints as they usually crack...

Additional info that might help is that 100% of the cases i am able to start the car if i connect the battery to another car's battery while their car is running... so if i jump start it then it is all fine, starts and the problem doesnt repeat itslef for another week or so... what can it be since jump starting works always... ????

Carsy

Just my pennies worth....

Often on this forum there are electrical problems you describe because of a low performing or faulty battery. You have replaced yours recently but I would like to ask whether it is one that has the correct capacity? (ie at least 70 Amp hour). MB recommend the Absorbent Glass Mat battery type also.

As you car starts whilst being jumped by another running car it points to your car needing extra voltage .

Why is this so ? Possible causes :-

Poor battery performance.

Corroded or badly fitted battery terminals.

Alternator or voltage regulator not charging your battery.

A system electrical leak discharging you battery.

A starter or solenoid which is worn ( brushes) & pulls extra amps to turn over your car.

Before expensive part replacements I would have a competent auto electrician check your battery ( load test) & alternator output.

What about putting a battery charger on overnight & see what the result is in the morning ?

Good luck.

JC

Glyn M Ruck

+1^

W203AL

Ok... now i have a pattern... I can provoke this problem by turning off the car and locking it while the Hazard flashers are ON... if i leave it like that for a while the car will not start and requires a jump start... what does this tell me ? :O

andrew_jackson

How many Amp Hours is your battery rated for?

Glyn M Ruck

Starting to sound as if your battery is only holding a surface charge. Have it load tested by a competent shop. If battery is deemed unhealthy make sure you get a decent 100 Ah battery as spec'ed by Benz.

W203AL

This is the second battery im using... i changed the one it had 1 month ago with a brand new one of 100Ah. When i run the tests the alternator is charging correctly and the motor starter is fine ... it seems like its progressing badly... until today it was happening once in like 2-3 weeks... but it happened today like 3 times... and now the SRS says SRS Visit workshop..... since i live in a country with no very good Benz Mechanincs this is a very frustrating issue... no one is able to provide a solution here......

Carsy

A system electrical leak maybe discharging you battery ?.Do an amp discharge test with a meter.. You may be able to go into engineering mode & check yourself.

What is your battery voltage without the engine running for 12 hours or so ?.

Use a trickle charger over night to see whether the problem exists in the morning .

Or disconnect the battery neg. terminal over night to see whether the error exists in the morning. This is fraught with danger .Careful reconnecting ( key removed)as there is always a risk of Sam failures with voltage spikes.

Where do you reside or is the CIA after you ?

Glyn M Ruck

I think JC has hit the nail on the head. The fact that this car always responds to jump starting shows low voltage. Spurious messages are also typical of low voltage. Unplug your seat modules & overhead console for now. They are the typical parasitic draw faults on a W203.

Check all electrical connections & earth straps.

Check the distribution block on the firewall for signs of burning or corrosion.

W203AL

My battery is always showing 12.6 V and this problem happens even 5 minutes after ive driven the car for 2 hours... i checked the alternator and it is fine... its charging the battery fine... on the other side there might be something that discharges it drastically for a very very short period of time (even 2 mins)... the thing is that on the pannel, even when it doesnt start it is always showing 12.6V and around 14.sth when running... im going nuts with this problem... I live in Albania and there are no good specialized mechanics here ... this forum seems to be my only hope

W203AL

Can it be the EIS ? I was thinking that since it responds to jump start it was not a EIS fault ...but can it be?

Glyn M Ruck

The good news is that if it behaves on a jump start it is not likely to be the ESL/EIS.

When you say won't start do you still mean "won't crank over"?

If your battery is healthy then you have a bad connection somewhere, A lazy starter solenoid or relay.

Also check temperature sender connection & CPS connection. Both are enterrogated before start enable.

W203AL

Yes... it doesnt crank at all... i turn the key and nothing... this is what happens, what it shows... i turn the key and before i try to crank it this is what appears... the sign of glow plugs never goes away so i can crank the car... OR it never shows up and i again can not crank the car.... all sorts of errors that appear, dissappear when i jump start the car ... when i diagnose it with STAR, all systems appear without any errors (except for the air conditioner which needs some repairs but thats a different story)

Please refer to this links...
One video shows the case when the glow plugs sign doesnt shut off and errors appear...the other the case when it doesnt appear at all... in both cases when i turn the key, the car doesnt crank at all...no noise no nothing...

http://www.youtube.com/watch?v=7WkkM...ature=youtu.be

http://www.youtube.com/watch?v=UenS_...ature=youtu.be

Thanks for the time you are spending on this case

W203AL

Extra info: I changed the solenoid of the motor starter and cleaned the motor starter as well so they are both in great condition, the battery is brand new as well...