A/C error KLA A 1257
Thread Starter
Junior Member
Joined: Apr 2017
Posts: 44
Likes: 1
From: Illinois
2002 E 430 4MATIC - 2008 S5504Matic
A/C error KLA A 1257
I have been searching the forum for more info on this but could not find anything that directly answered my problem.
This is For The 2004 S430 4Matic
So my compressor went out, I replaced it, added proper amount of oil, new electrical connector to the compressor because the original one broke apart when I took it off and replaced the Dryer.
I put a vacuum on it and it went down to where it should. I closed off the manifold gauge and it kept the vacuum for an hour. I continued to pull the vacuum after that for an hour. All was good it held great.
So now I go to charge it and the AC light wont go off. I go to Diagnosis and get that error. I erase it and the light goes off for about 1 or so minutes and then goes on. In that time the compressor never sucks in any refrigerant and the error gets tripped again.
So now what?
It held the vacuum like it should so no leaks but how do I clear the code and get it to suck in the refrigerant?
This is For The 2004 S430 4Matic
So my compressor went out, I replaced it, added proper amount of oil, new electrical connector to the compressor because the original one broke apart when I took it off and replaced the Dryer.
I put a vacuum on it and it went down to where it should. I closed off the manifold gauge and it kept the vacuum for an hour. I continued to pull the vacuum after that for an hour. All was good it held great.
So now I go to charge it and the AC light wont go off. I go to Diagnosis and get that error. I erase it and the light goes off for about 1 or so minutes and then goes on. In that time the compressor never sucks in any refrigerant and the error gets tripped again.
So now what?
It held the vacuum like it should so no leaks but how do I clear the code and get it to suck in the refrigerant?
Super Member
Joined: Sep 2012
Posts: 690
Likes: 76
From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
2 things:
If lo pressure the system gets shut down for protection.
Once recharged (You can do that by introducing liquid into the high pressure line without the engine running (one can)), you need to reset the system to clear the shut down fault.
Then run it and charge the rest (all by quantity, not pressure).
Good luck!
If lo pressure the system gets shut down for protection.
Once recharged (You can do that by introducing liquid into the high pressure line without the engine running (one can)), you need to reset the system to clear the shut down fault.
Then run it and charge the rest (all by quantity, not pressure).
Good luck!
Last edited by kraut56; Jul 29, 2019 at 12:18 PM.
Thread Starter
Junior Member
Joined: Apr 2017
Posts: 44
Likes: 1
From: Illinois
2002 E 430 4MATIC - 2008 S5504Matic
Have you ever done that? Added to the High side? That kind of scares me a bit. Are you saying just connect the high side to a can of, upside down, refrigerant to get the stuff to go into the line?
I can only get the error to go out for a minute or two and the compressor refuses to turn on.
I can only get the error to go out for a minute or two and the compressor refuses to turn on.
Super Member
Joined: Sep 2012
Posts: 690
Likes: 76
From: Montreal, Quebec
2009 E350 4M Avantgarde;mistress 2002 S600; wife 2014 C300 4M
you need some pressure in the system (charging it without the engine running into the high pressure port).
Then, you need to get into the center display and go into the HACV menu and reset the system.
after that, you can charge the rest with engine running thru the LO pressure side.
Read, read and know what you are doing!
Good luck!
Then, you need to get into the center display and go into the HACV menu and reset the system.
after that, you can charge the rest with engine running thru the LO pressure side.
Read, read and know what you are doing!
Good luck!
Senior Member
Joined: Apr 2019
Posts: 428
Likes: 96
From: Houston
001 s600, 94 sl600
When the compressor does start, it quickly sucks down the lo-side pressure (and will shut the compressor OFF due to low pressure.
The CORRECT charging procedure is to vacuum out the system to less than 50 microns, shut off the vacuum pump and let things sit for an hour to check for any leaks. Then connect refrigerant canto the LOW side and Hi side, adding up to the 'full charge' weight. Then start the car etc.
NEVER connect a refrigerant can to the Hi side with the compressor running---the compressor discharge pressure can explode the can.
The CORRECT charging procedure is to vacuum out the system to less than 50 microns, shut off the vacuum pump and let things sit for an hour to check for any leaks. Then connect refrigerant canto the LOW side and Hi side, adding up to the 'full charge' weight. Then start the car etc.
NEVER connect a refrigerant can to the Hi side with the compressor running---the compressor discharge pressure can explode the can.
Thread Starter
Junior Member
Joined: Apr 2017
Posts: 44
Likes: 1
From: Illinois
2002 E 430 4MATIC - 2008 S5504Matic
I thought I was clear on what I did on my original post, you described EXACTLY what I did except I think I left it under a vacuum for about an hour and a half or so. There are absolutely no leaks and it held the vac perfectly.
As I said I connected the can to the Low side but the compressor would not suck anything in because of the error. I was able to clear that error only temporarily which was not nearly long enough to get the compressor to suck anything in.
I wanted to know if anyone had this happen where the car is saying it will not turn the compressor on because of the low refrigerant. Obviously it is low it is empty. The car will not accept any refrigerant.
How do I get the car to keep the error cleared and let the compressor suck in the can of refrigerant?
As I said I connected the can to the Low side but the compressor would not suck anything in because of the error. I was able to clear that error only temporarily which was not nearly long enough to get the compressor to suck anything in.
I wanted to know if anyone had this happen where the car is saying it will not turn the compressor on because of the low refrigerant. Obviously it is low it is empty. The car will not accept any refrigerant.
How do I get the car to keep the error cleared and let the compressor suck in the can of refrigerant?
