ECU issue?

[Mujahid]

Hi, my name is Mujahid. I have owned a W204 C180K 2007 for about 2 and a half years. No major issues up until now. My car doesn't start when turning the key and I get the the ESP inoperative sign and cruise control inoperative. I also notice a clicking sound from the SAM module area after the car has been swithced off. I've taken it to the garage and they've said that the ECU is not communicating with the ABS, gearbox and engine management modules. This could be an ECU fault but he said he is liaising either MB tech support for further advice. He said that he noticed some corrosion and possible signs of water ingress. He alsp mentioned replacing the ECU, but I'm worried that after spending a lot on a new ECU, that the issue remains. Any advice?

 

[markjay]

How did you take the car to garage - you say it does not start - and where is the car now?

The first thing to check is the main battery... is the voltage OK? I would first ensure that the battery is fully charged, if you can then buy a trickle charge and charge it overnight.

If this does not help, then make sure you take the car to an MB specialist, who can diagnose the fault correctly. Water ingress can affect any electrical component, so this needs to be verified before replacing the ECU or other parts.

Where in the UK are you? Someone mind recommend a good specialist local to you.

 

[Mujahid]

Thank you for the reply. It was recovered from my drive to a local garage and it is still there. The battery was only a year old, plus a new battery was put in and tested, still not working. I live in Grays.

 

[Mujahid]

How did you take the car to garage - you say it does not start - and where is the car now?

The first thing to check is the main battery... is the voltage OK? I would first ensure that the battery is fully charged, if you can then buy a trickle charge and charge it overnight.

If this does not help, then make sure you take the car to an MB specialist, who can diagnose the fault correctly. Water ingress can affect any electrical component, so this needs to be verified before replacing the ECU or other parts.

Where in the UK are you? Someone mind recommend a good specialist local to you.

I took it to a MB specialist. They confirmed it wasn't an ECU issues, they have found water inside the car. They're trying to find out how the water got in there and check which connections have been damaged.

 

[softradeau]

Hi, my name is Mujahid. I have owned a W204 C180K 2007 for about 2 and a half years. No major issues up until now. My car doesn't start when turning the key and I get the the ESP inoperative sign and cruise control inoperative. I also notice a clicking sound from the SAM module area after the car has been swithced off. I've taken it to the garage and they've said that the ECU is not communicating with the ABS, gearbox and engine management modules. This could be an ECU fault but he said he is liaising either MB tech support for further advice. He said that he noticed some corrosion and possible signs of water ingress. He alsp mentioned replacing the ECU, but I'm worried that after spending a lot on a new ECU, that the issue remains. Any advice?

I have similar symptoms on my vito w639 120. Initially started after a number of flat battery incidents due to not doing very many kilometres due to covid lock down. Starts with random ASR light on dash about 5 minutes of driving and I thought, the first time, at the next set of lights I will restart the car and the fault will clear. But embarrassingly it would not start and lights came on as normal but wouldnt crank. After getting pushed off the road I thought I will try removing the earth lead of the battery for a couple of minutes then putting it back on. Great it started and when I got home Star Diagnostic only gave errors re could not communicate with EZS from ESP CDI which I cleared and all good for 6 weeks. Then everyday after this from cold start same thing ASR light with beep comes on around 3 to 5 minutes after start. Also aircon and cruise control stop but engine runs until it is shutdown. Then won't start. I found that CDI and ABS/ESP could not be seen by Star and all errors refer to no communication with CDI and ESP with EZS. Instead of disconnecting the earth lead pulling the 7.5 fuse (Ignition lock) when key turned off you can start and CAN C CDI & ESP communicate again. No real meaningful fault code other than what is above. I took it to my local MB Indy and he suggested I call a crowd that do ecu repairs.
I changed the brake light switch and the problem went away but returned again 6 weeks later.
So I went and bought another brake light switch but no go.
So now I believe it is a wiring issue to the ECU. In the meantime I am getting the SAM and EZS
tested. While that is happening I am going to inspect ECU harness.
ECU repairer thinks it is the EZS or damaged wiring where harness might rub or vibrate.
If anyone has a suggestion please let me know.

 

[softradeau]

I have similar symptoms on my vito w639 120. Initially started after a number of flat battery incidents due to not doing very many kilometres due to covid lock down. Starts with random ASR light on dash about 5 minutes of driving and I thought, the first time, at the next set of lights I will restart the car and the fault will clear. But embarrassingly it would not start and lights came on as normal but wouldnt crank. After getting pushed off the road I thought I will try removing the earth lead of the battery for a couple of minutes then putting it back on. Great it started and when I got home Star Diagnostic only gave errors re could not communicate with EZS from ESP CDI which I cleared and all good for 6 weeks. Then everyday after this from cold start same thing ASR light with beep comes on around 3 to 5 minutes after start. Also aircon and cruise control stop but engine runs until it is shutdown. Then won't start. I found that CDI and ABS/ESP could not be seen by Star and all errors refer to no communication with CDI and ESP with EZS. Instead of disconnecting the earth lead pulling the 7.5 fuse (Ignition lock) when key turned off you can start and CAN C CDI & ESP communicate again. No real meaningful fault code other than what is above. I took it to my local MB Indy and he suggested I call a crowd that do ecu repairs.
I changed the brake light switch and the problem went away but returned again 6 weeks later.
So I went and bought another brake light switch but no go.
So now I believe it is a wiring issue to the ECU. In the meantime I am getting the SAM and EZS
tested. While that is happening I am going to inspect ECU harness.
ECU repairer thinks it is the EZS or damaged wiring where harness might rub or vibrate.
If anyone has a suggestion please let me know.

This turned out to be a faulty ezs. Even after an ECU repair organisation had tested and said no faults in the ezs. After getting a second hand ezs and re coding to my vin all good.