W203 Doesn't start/does not crank
Thread Starter
Junior Member
Joined: Jan 2014
Posts: 32
Likes: 0
C-Class W203 2004
Well, i fixed the ECU and so far no problems... i was told the ECU had physical problems and software problems.
I will update the thread in 1 month and report if there are any errors... otherwise i really hope i have solved the problem
Hope this thread will help others...
cheers.
I will update the thread in 1 month and report if there are any errors... otherwise i really hope i have solved the problem
Hope this thread will help others...
cheers.
Super Member
Joined: Mar 2012
Posts: 968
Likes: 62
From: San Francisco, CA
2005 c230SS
It's been a little over a year now ... is your problem solved? I just had a non-start episode this morning so I may be in for the same troubleshooting experience ...
Thanks. John
Thanks. John
Last edited by jkowtko; Apr 12, 2019 at 09:18 AM.
Junior Member
Joined: May 2018
Posts: 16
Likes: 1
From: Reading, UK
C220 CDI Coupe 2002
Intermittent Cranking Start problem in mornings
Hello everyone,
I have exactly the same problem as you describe happening more and more frequently on the mornings only.
I can insert they key, I can hear bzzzz, Key is accepted by immobiliser and locked in position, position2: ignition lights come on as normal, glow plugs and air-bag lights disappear after while, so all OK, no errors. Relays are clicking as normal.
Turning the key into position3: nothing, starter motor is not giving a sound.
After 30min trying, locking-unlocking finally I can start the car.
The problem is not happening during the day, only on the mornings.
I did check described by you relays, fuses and obviously looking poor connectors but I cannot find anything obvious. I swapped relays and fuzes, cleaned connectors with electric liquids. I disconnected the negative battery plug for 30min. Car cracks normally in the evening, but when I tried in the morning the issue still was the same 30min trying and finally it started.
Fuse 52,57,31 checked, removed & tested,
Starter motor relay "R" removed & tested with meter under load, also swapped with another one with the same parameters. M, P, B, F relays also are also looking to be working OK.
I have 2 keys, problem happens with either of them in the same way.
I'm going to replace Fuse 52 (15A with 20A) today. Then I'm running out of options.
Car: Mercedes C220 CDI Coupe (W203), year 2002, 6 Speed Manual.
Please assist. I'm running out of options.
Here I also saw that fuel pressure needs to be above 3.8 bar / 55PSI for cranking to be allowed. Is it easy to test the pressure using home tools or I need specialist hand?
https://mbworld.org/forums/c-class-w...t-process.html
I have exactly the same problem as you describe happening more and more frequently on the mornings only.
I can insert they key, I can hear bzzzz, Key is accepted by immobiliser and locked in position, position2: ignition lights come on as normal, glow plugs and air-bag lights disappear after while, so all OK, no errors. Relays are clicking as normal.
Turning the key into position3: nothing, starter motor is not giving a sound.
After 30min trying, locking-unlocking finally I can start the car.
The problem is not happening during the day, only on the mornings.
I did check described by you relays, fuses and obviously looking poor connectors but I cannot find anything obvious. I swapped relays and fuzes, cleaned connectors with electric liquids. I disconnected the negative battery plug for 30min. Car cracks normally in the evening, but when I tried in the morning the issue still was the same 30min trying and finally it started.
Fuse 52,57,31 checked, removed & tested,
Starter motor relay "R" removed & tested with meter under load, also swapped with another one with the same parameters. M, P, B, F relays also are also looking to be working OK.
I have 2 keys, problem happens with either of them in the same way.
I'm going to replace Fuse 52 (15A with 20A) today. Then I'm running out of options.
Car: Mercedes C220 CDI Coupe (W203), year 2002, 6 Speed Manual.
Please assist. I'm running out of options.
Here I also saw that fuel pressure needs to be above 3.8 bar / 55PSI for cranking to be allowed. Is it easy to test the pressure using home tools or I need specialist hand?
https://mbworld.org/forums/c-class-w...t-process.html
Last edited by adam.itech; May 22, 2018 at 09:31 AM.
Junior Member
Joined: May 2018
Posts: 16
Likes: 1
From: Reading, UK
C220 CDI Coupe 2002
Hey Everyone! I think I managed to resolve my problem with "Early Morning no Cranking"! and would like to share it with you.
I pulled and cleaned again all connectors I could see in the engine bay. On the NSF near break pump, close to wheel arch, there is some sort of regulator, with 2 connectors and bigger ground cable, which was a bit corroded. I properly cleaned that one. I think this fixed “no cranking problem”.
The only meaningful error I saw on the BOSH ODB scanner was: "P0100 Mass or volume air flow circuit too high" and no other related messages which people say usually should come up. I cleared all errors afterwards.
The local Mercedes specialist told me that there were problematic ESP modules fitted in 2002-2006, after that they used working correctly modules. This most likely caused an issue in my case and somehow after a few shakes that started working again (for who knows how long).
Now, I have left with another issue which happened in the middle of the cold start problem: When the engine is cold, everything works fine. When the engine gets warm, something in electronics triggers and is not allowing me to go above 3K RPM. P0100 code is the only one I get.I put the post here https://mbworld.org/forums/c-class-w...100-error.html
Please help out if you can
I pulled and cleaned again all connectors I could see in the engine bay. On the NSF near break pump, close to wheel arch, there is some sort of regulator, with 2 connectors and bigger ground cable, which was a bit corroded. I properly cleaned that one. I think this fixed “no cranking problem”.
The only meaningful error I saw on the BOSH ODB scanner was: "P0100 Mass or volume air flow circuit too high" and no other related messages which people say usually should come up. I cleared all errors afterwards.
The local Mercedes specialist told me that there were problematic ESP modules fitted in 2002-2006, after that they used working correctly modules. This most likely caused an issue in my case and somehow after a few shakes that started working again (for who knows how long).
Now, I have left with another issue which happened in the middle of the cold start problem: When the engine is cold, everything works fine. When the engine gets warm, something in electronics triggers and is not allowing me to go above 3K RPM. P0100 code is the only one I get.I put the post here https://mbworld.org/forums/c-class-w...100-error.html
Please help out if you can
Last edited by adam.itech; Jun 12, 2018 at 06:53 AM.
Junior Member
Joined: May 2018
Posts: 16
Likes: 1
From: Reading, UK
C220 CDI Coupe 2002
Now my car is not wanting to start again after happily turning the starter motor for almost a year with no problems. In the meantime, I put a new 100AH battery, 5 months ago. I also replace faulty MAF. Now I don't have any error codes popping up on the dashboard or ELM OBD2.
I was able to start the car earlier with this weird behaviour of opening and closing passenger doors with a bit of a force. It used to shake something and the car was starting. Now, this trick does not work any more.
I'll try the earlier mentioned trick with using another running car to start Merc with jump leads. Extra power might let me start it to get into the workshop at least. And I'll look for this clutch switch (could you let me know, where is it located - I'm still a newbie in this area).
Once I get access to STAR, maybe I will know why it seems like the power is not getting into the starter motor at all and what is causing it.
When I put the key in position 3 (ignition), OBD2 signalised a tiny drop in voltage, so looks like things are OK here but where they are not?
I was able to start the car earlier with this weird behaviour of opening and closing passenger doors with a bit of a force. It used to shake something and the car was starting. Now, this trick does not work any more.
I'll try the earlier mentioned trick with using another running car to start Merc with jump leads. Extra power might let me start it to get into the workshop at least. And I'll look for this clutch switch (could you let me know, where is it located - I'm still a newbie in this area).
Once I get access to STAR, maybe I will know why it seems like the power is not getting into the starter motor at all and what is causing it.
When I put the key in position 3 (ignition), OBD2 signalised a tiny drop in voltage, so looks like things are OK here but where they are not?
Junior Member
Joined: May 2018
Posts: 16
Likes: 1
From: Reading, UK
C220 CDI Coupe 2002
Back to basics check SAM properly -Relay S + Fuse 52 connections + wires in front SAM
Front SAM C220 CDI
Merc garage replaced a few relays, as they come up as not working well in STAR, yet I started to have the intermittent problem with starting a car again. Taking Relay S out and putting is back worked a few times. Then I started to have a new series of car not starting for 30min of trying. I can feel and hear Relay S and others clicking, but it looks like power is not going to starter motor still. I can’t see any corroded area or any obvious problem. This pict can help for starters - focus on Relay S + Fuse 52
Last edited by adam.itech; Apr 22, 2019 at 10:02 AM.
Junior Member
Joined: May 2018
Posts: 16
Likes: 1
From: Reading, UK
C220 CDI Coupe 2002
After having the wiring with a control bulb done to the starter motor, I observed that power is going to it (so the signal is going too!!!), but there were these annoying occasions, where the starter motor didn't want to start cranking. I had enough of not knowing when the car would not want to start. I have replaced the whole starter motor. I think the new starter motor is cranking a bit faster. You can play with replacing starter motor brushes, solenoids, checking connectors for rust deposits. I simply had enough on this occasion.
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Newbie
Joined: Jun 2024
Posts: 2
Likes: 0
W203 c320
M
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... ????
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... ????
Newbie
Joined: Dec 2024
Posts: 2
Likes: 0
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 ((
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 ((
Member
Joined: Jul 2024
Posts: 119
Likes: 12
From: SoCal
90 VW Corrado g60, 07 New Beetle Vert triple white & 09 Escalade ESV Plat LOL!
I started reading this from #1 too and couldn’t believe how informative it was. Didn’t check the timeline until post #7.
Cliffnotes … always slow charge your battery disconnected from the car, then bring it to a shop / store so it can be load tested for a bad cell.
Cliffnotes … always slow charge your battery disconnected from the car, then bring it to a shop / store so it can be load tested for a bad cell.
Newbie
Joined: Mar 2026
Posts: 3
Likes: 0
2005 c230 K w203
Evening,
First of all...... WOW the information in this is crazy!
I'm having no crank no start issues.
I have never heard this car turn over since I purchased it in November of last year (2025)
2005 C230 K W203
Here is my diagnosis list:
EIS: GOOD
15
15R
15C
50 (When key turned)
Ruled this EIS as not the issue
ME: GOOD
Had inspected by ECU-Pro
ECU is coded correctly and is working properly.
EZS: BAD
no start enable.
Both original starter and borrowed horn relay function as should.
Ability to jump 30 and 87 and turn the engine over but will not fire.
Voltage at 30 and 87 holds at battery voltage.
Voltage at 85 and 86 is battery voltage.
Fuses: Good
PURPLE SIGNAL WIRE:
Back probed the purple signal wire.
With my sons help turning the key, There was no voltage present.
Could this be due to the EZS no start enable?
Battery voltage with charger steady at 13V
I am leaning towards pulling the front SAM and looking for broken pins or corrosion.
The EZS has me stumped too.
Thanks in advance for any help or advice.
First of all...... WOW the information in this is crazy!
I'm having no crank no start issues.
I have never heard this car turn over since I purchased it in November of last year (2025)
2005 C230 K W203
Here is my diagnosis list:
EIS: GOOD
15
15R
15C
50 (When key turned)
Ruled this EIS as not the issue
ME: GOOD
Had inspected by ECU-Pro
ECU is coded correctly and is working properly.
EZS: BAD
no start enable.
Both original starter and borrowed horn relay function as should.
Ability to jump 30 and 87 and turn the engine over but will not fire.
Voltage at 30 and 87 holds at battery voltage.
Voltage at 85 and 86 is battery voltage.
Fuses: Good
PURPLE SIGNAL WIRE:
Back probed the purple signal wire.
With my sons help turning the key, There was no voltage present.
Could this be due to the EZS no start enable?
Battery voltage with charger steady at 13V
I am leaning towards pulling the front SAM and looking for broken pins or corrosion.
The EZS has me stumped too.
Thanks in advance for any help or advice.
