M278 IC-Pump (CWA100) always on

Old Mar 25, 2026 | 07:33 AM
  #26  
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Yes it is if you have the small IC coolant reservoir between the intake boxes. Separate IC system is a totally different thing than this.

You need to manage out that diagram system M157 and M157 + 014. That 014 system is the best system that only M157 S (585hp) models use. It's the only system that have the extra HE to help IC cooling. Not any M278 cars or even standard M157 AMG don't have it.
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Old Mar 25, 2026 | 07:59 AM
  #27  
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Originally Posted by PekkaH
Yes it is if you have the small IC coolant reservoir between the intake boxes. Separate IC system is a totally different thing than this.

You need to manage out that diagram system M157 and M157 + 014. That 014 system is the best system that only M157 S (585hp) models use. It's the only system that have the extra HE to help IC cooling. Not any M278 cars or even standard M157 AMG don't have it.
I have a 2015 with M278 and these have the small IC coolant reservoir between the intake boxes.

If your system is working fine, then I will go the same way and connect it like you did.

Last edited by slobo; Mar 25, 2026 at 08:09 AM.
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Old Mar 25, 2026 | 08:31 AM
  #28  
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Originally Posted by slobo
I have a 2015 with M278 and these have the small IC coolant reservoir between the intake boxes.

If your system is working fine, then I will go the same way and connect it like you did.
Heh we all have our own builds and of course you can do what suits you best. Im just trying to help you to see what needs to be done and what is what, when adding an extra IC HE to your current system.

Here is a picture of M278 split cooling system that you and I and M278 maybe after 2012 -2013 all have. This might clear things.



You are now updating this your system to be kind of similar that M157 + M 014 is. You can read and see the pictures, diagrams, part numbers that I list in this topic.

I have also swap the M157 center big IC HE and (can be seen on my built topic) You need a custom hose to your center HE to CWA100. All other part numbers you can find here. Or just make all custom. Its up to you.

This might help you now understand the difference between separate IC cooling system and M157 + M 014 system.
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Old Mar 25, 2026 | 09:08 AM
  #29  
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Originally Posted by PekkaH
Heh we all have our own builds and of course you can do what suits you best. Im just trying to help you to see what needs to be done and what is what, when adding an extra IC HE to your current system.

Here is a picture of M278 split cooling system that you and I and M278 maybe after 2012 -2013 all have. This might clear things.



You are now updating this your system to be kind of similar that M157 + M 014 is. You can read and see the pictures, diagrams, part numbers that I list in this topic.

I have also swap the M157 center big IC HE and (can be seen on my built topic) You need a custom hose to your center HE to CWA100. All other part numbers you can find here. Or just make all custom. Its up to you.

This might help you now understand the difference between separate IC cooling system and M157 + M 014 system.
Thank you for taking the time and effort to explain everything to me. This modification will give me a good, stable IAT. Then I’ll be able to push the car clean from 100–250 km/h.
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Old Mar 25, 2026 | 08:44 PM
  #30  
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CWA100 code is usually related to a faulty IC pump or an electrical issue, I've had a few people on here mention a faulty T-stat that causes it too. If it's always on you might want to check the T-stat and IC pump itself for any leaks or debris that might be causing the malfunction.
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Old Mar 26, 2026 | 10:28 AM
  #31  
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Originally Posted by PekkaH
In the trunks fuse box.
Could you tell me which number or which Fuse exactly. I don't have a plan or a diagram of the fuse box.
Edit: Is it number 46?

Last edited by slobo; Mar 26, 2026 at 11:08 AM.
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Old Mar 26, 2026 | 01:59 PM
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Originally Posted by slobo
Could you tell me which number or which Fuse exactly. I don't have a plan or a diagram of the fuse box.
Edit: Is it number 46?
Might be and also check 70. Sorry I don't have the diagram right now with me (should found in internet ) but tomorrow I can see those for sure for you.
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Old Mar 28, 2026 | 04:40 AM
  #33  
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Hi. Check fuses 46, 70 and 87.
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Old Mar 28, 2026 | 04:18 PM
  #34  
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Originally Posted by PekkaH
Hi. Check fuses 46, 70 and 87.

I think it's 46, because there was a 7.5A which I changed and put a 15A. But I think it's not running. Water is not moving in the small reservoir. Today I was working with vacuum, but it doesn't help me. 😭
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Old Mar 28, 2026 | 04:39 PM
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Oh sorry to hear that. Yes that fuse 46 was burn in my case. 7.5A is good to run it. You need to put the car to the lift and use Xentry or jump wire to run the pump and squish and pump and make the pressure to that hose that goes to the CWA100. I did need to do that first time. If that won't help, the wiring adapter is bad for some reason. I haven't heard that CWA100 is bad from factory, or that pump goes bad even it's old. Or you have the first bad CWA100 that I ever know. There really can't be any other options that I see.
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Old Mar 29, 2026 | 07:34 PM
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Originally Posted by PekkaH
Oh sorry to hear that. Yes that fuse 46 was burn in my case. 7.5A is good to run it. You need to put the car to the lift and use Xentry or jump wire to run the pump and squish and pump and make the pressure to that hose that goes to the CWA100. I did need to do that first time. If that won't help, the wiring adapter is bad for some reason. I haven't heard that CWA100 is bad from factory, or that pump goes bad even it's old. Or you have the first bad CWA100 that I ever know. There really can't be any other options that I see.
Today I tried everything. But I think the pump doesn't work. IAT is too high. I will check tomorrow the wiring adapter.
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Old Apr 15, 2026 | 10:31 AM
  #37  
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Originally Posted by slobo
Today I tried everything. But I think the pump doesn't work. IAT is too high. I will check tomorrow the wiring adapter.
Was the wiring adapter faulty?
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Old Apr 15, 2026 | 07:41 PM
  #38  
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Originally Posted by PekkaH
Was the wiring adapter faulty?
I don't have time to check it, because we were working on the brakes: 6 pot calipers from CLS 63 AMG with OEM CLS 500 rotors.


Maybe next week I will find some time to check the IC pump.. 😔

Last edited by slobo; Apr 15, 2026 at 07:43 PM.
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Old May 5, 2026 | 05:35 PM
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Originally Posted by PekkaH
Was the wiring adapter faulty?
Yes.. Tobi made a mistake with the cables



The ground and the plus are on the wrong position, I hope you can see it. 🙈🤯

Tomorrow I will go to a car electrician to fix that. Hope the pump will work after that as it should. 🙏🏻
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Old May 10, 2026 | 03:23 PM
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Friday night I realized, that one of the two pins is too short to made some connection. So the adapter was also from this perspective useless. Then I cut the housing and made a connection. Now it works but this is only provisional. 🙈
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