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Discussion Starter #1
On my last road trip my AC compressor shut down (2000 W210 – E55) and the EC light became stuck in the on position. I searched many threads and even spoke to my local Indy Benz tech who told me I would have to bring the car to a MB tech who can clear the codes. Many posts I found confirmed this, saying you can’t clear the codes without hooking up to the DAS/STAR system. This in fact is NOT true.

After reading my codes I realized the system shut off the compressor due to low refrigerant pressure. When refrigerant pressure reaches about 8-7 bar or lower the compressor automatically shuts itself down, therefore making it impossible to recharge since the compressor will not pull in 134a. Once I cleared codes (easily), I was able to hook up a can of 134a to the low side line and charge the system successfully. If you have the same problem and no leaks (or very slow) you should be able to rectify this with a $30 can of 134a and some simple button pushing. The following menus should help you diagnose what is wrong with your system. I am not a MB tech nor do I profess to be one so I need to throw in the disclaimer – proceed with caution and at your own risk. I have made every attempt to compile clear and accurate info to help anyone else out that has gone through the same issue I have or other AC issues.

RETRIEVE DATA:

Turn on ignition (run car)
Put both sides Temp settings at 72
Push and hold “REST” button till you get a 1 in the left side
Push the left “AUTO” button to scroll forward and right auto button to scroll back.
Let the car run 3 minutes before pulling data to ensure more accurate data
For AC diagnosis you only need to be concerned about codes 1 through 8

Code 1 = Inside Temp
Code 2 = Outside Temp
Code 3 = Left Core Temp
Code 4 = Right Core Temp
Code 6 = Coolant Temp
Code 7 = Refrigerant Pressure (This is the important one)
Code 8 = Refrigerant Temp


PULLING FAULT CODES

Switch ignition on
Set left AC/heater temperature control to HI
Set right AC/heater temperature to LO
Depress REST and EC switches simultaneously within 20 seconds of turning ignition on
Hold REST and EC switches for more than 5 seconds
Air recirculation lamp flashes
Depress right AUTO switch repeatedly. Note trouble codes
FF is not a code

What the codes mean:
003 B1226 In-car temperature sensor with blower
005 B1228 Heater output temperature sensor
006 B1229 " " "
007 B1230 AC evaporator temperature sensor
008 B1231 Engine coolant temperature (ECT) sensor
009 B1232 AC refrigerant pressure sensor
010 B1233 AC refrigerant temperature sensor
011 B1234 AC sunlight sensor
012 B1235 Heater intake air purity sensor
013 B1241 AC refrig pressure sensor, AC temp pressure sensor refrigerant level
014 B1416 Engine coolant pump motor
019 B1417 Engine coolant heater regulator valve LH
020 B1418 " " RH
021 B1419 AC compressor clutch
022 B1420 Idle speed increase
023 B1421 Engine coolant blower motor control module
024 B1422 Serial interface K1
025 B1423 AC heater valve block
026 B1424 AC heater air intake filter actuator
027 B1425 " "
029 B1429 Serial interface K2


RESETTING FAULT CODES:

In fault code mode press both “AUTO” switches simultaneously for more than 5 seconds (after last trouble code is displayed)
Once codes are cleared you will see display change to "d and FF"
Switch ignition OFF – All Codes are erased


REFILLING SYSTEM:

Purchase a larger refill can of 134a with a gauge on it so you can read the low side pressure – helps as a guide to filling the system to the correct level. The instructions on the can will tell you what pressure to fill based on the ambient temp. You can find this refill can at any Walmart/Target/Auto Store for $20-$30. Make sure you purge the can before you fill:


Shake can
Squirt a very small amount of refrigerant to purge air out of the hose – you don’t want to introduce any air to your system.
Start car
Connect to low side port (drivers side left of engine mid bay with plastic black cap on it - unscrew)
Turn off EC button (light goes out and compressor goes on)
Read the PSI gauge on the can filler (should be low) around 20 psi or less
Pull trigger while gradually shaking the can and holding it upside down until it reaches instructed pressure depending on Ambient temp.
Once system is recharged it should be blowing cold air
Follow up by reading Code 7 – mine was originally 7 bar and became 17 bar after recharge. Also make note of the recharged bar pressure(17) – you can periodically check code 7 to make sure the system is holding the refrigerant pressure – if it decreases over time you have a slow leak and need to address it.

Hope this helps and good luck!
 

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Discussion Starter #3
I threw three codes:

1243 (Sunsenor)
1416 (Compressor)
1241 (Low refrigerant)

this in conjunction with only 7 bar of pressure on the code 7 reading indicated I was low on refrig. If code 7 is less than 10 then more than likely this is your issue.
 

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world of hurt...

so i did exactly as i should.
18 oz. of 134a then a can of interdynamics sealant then another 12 oz can of 134a...

and my code 7 was only at 15....then 15 minutes later it was at 14. and the a/c isnt blowing as cold as it used to...

i have a big leak... and the summer is coming.
 

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Air con recharge but EC still on.

Hi,
Having read your a/c issue I am unsure where to go now.

My EC led came on a few weeks ago and stayed on.
Eventually I read on the forum that this refers to refrigerant drop of more than 28%.
I booked the car in and had it recharged at a Kwik fit garage.

the machine used automatically checks the resident gas and oil then checks for leaks then charges the system with in my case 850G of R135.

Switched on and EC light still lit, air con still not working.

The printout after it had finished showed no oil or gas at all in the system when it first started!

I note there are 2 fuses shown which are 41 and 51 so I will check these but lost for ideas now.
Grateful for any help.
Tim
http://www.benzworld.org/forums/images/smilies/confused.gif
C200K evolution sport coupe 2001
 

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fuse plan inside shows A203 545 02 00

Does this mean my model / chassis is A203 or are these number arbitary?

model is C200K sport coupe with evolution roof.
Fuse info attached if of any use.
Tim
 

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Discussion Starter #8
Tim

Once your Ac system goes into fault mode (the EC light permently on) it will not work if you don't clear the codes. You MUST clear the code manually as stated in my above comments, refilling system, pulling fuses or disconnecting battery will not do a thing. You must clear the codes from the AC module in the car...

My car is the w210 chasis so not sure if it will work on a203.Read the first post and pull faults codes on the AC module (where you control your temp in the car) and then clear the faults - this will enable your AC - otherwise you need to plug in and have das/star clear codes for $$$$.

good luck
 

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Air con recharge but EC still on. codes access?

Thanks LEOMD
I have taken a photo of my climate control because I have no rest switch, only the ones shown.

Where is the reset as referred to on the main display?
I have tried a few combinations but to no avail.

I do have an ODB2 reader that can reset engine management codes but not these.

Do I need to have a dealer reset the codes or is there still hope.
Regards
Tim
 

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Discussion Starter #10
Tim:

Yes - looks like a totally diff system - therefore the w210 manual reset will not work. OBDII will not pull or reset AC codes. I could be wrong but I do believe that there must be a way to retrieve the error codes and reset them manually via some button combinations etc. I would check more on forums specific to your chassis and see if you can find something to read or reset codes - I don't see why Benz would not include under newer models.

If you cant find anything find a friend or a local independent shop that has access to the computer so they can plug in and clear your codes - dealer charges crazy money so I always see them as a last resort. I dont see it being more than a 5 minute operation. Thats the problem with most AC shops - they can service your AC system but they cant check or clear codes specific to your system.

Good luck
 

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Leo,
I read on eclassbenz.com that the freon pressure sensor that provides the readings for sensor 7 above can fail and provide low reading around 0 or 0, which would prevent the compressor from starting. There is a secondary sensor in the compressor that can be selected as the source for reading #7. See procedures on that site (search "how-to-diagnose-air").

And finally, I do see a few people just loading a lot of freon into the car with not much concern to over-pressure. You should always use the cans that come with a gage and only fill the low pressure port when the compressor clutch is engaged. If you don't know what it means then may be you need help from someone who knows.

Since my EC light was constantly on and the reading #7 was 04 and I had 3 error codes, I went ahead with the reset procedure you provided above (so easy wow). Immediately I could turn off the EC light and the compressor kicked in. The pressure immediately jumped to 8 as I had been trying to charge before but the low pressure port had too much pressure. I then plugged the ac refill bottle and charged some more. It settle down at around 13 with the engine idle (it went up to 18 when rpm=2000). Air coming out of vents is cold and everything is cool.

Thanks for the sharing.
Besides this post, the only other thing that could have happened would be a failed pressure sensor in which case the procedure on the other site above may help. But I would always start from the reset procedure first. If a malfunction is still in place the error code will be set right away again and you would know that a serious problem may be at hand, in case selecting the backup pressure sensor does not help.
 

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hi i have an 06 slk280 with the climate control not working rest button tights up red had a/c regassed but need the reset the climate control will you instructions work for my car
thanks kev...
 

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Leo Thanks for posting this procedure.
I just tried this because my AC isn't as cold as it should be There were no error code's
and #7 was 15 . Does a reading of 15 mean the freon is OK .

Tks Bill
 

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DL - I would find a competant aircon shop for around $80 or less to evacuate the existing refirdgerant, holkd at vacuum to check for major leaks, then they will refill with 100% fresh refridgerant to restore the system.

Keep the beat !
 

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DL - I would find a competent aircon shop for around $80 or less to evacuate the existing refrigerant, hold at vacuum to check for major leaks, then they will refill with 100% fresh refrigerant to restore the system.

Keep the beat !
Made it to the shop today. Took about 40 minutes on his scanner to clear the codes. The fan did not seem to want to kick on. Finally about 250-260 pressure. Seems a little high, 225ish would seem more common. 134 is weird stuff, and can give false readings. Anyways, I"ll see how far a re charge gets me , and if i have a slow leak or not. Nice to have some AC again since it was 99F here today..

thanks,
DL
 

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I would recommend you post the current AC values in the W210 forum (rather than the AMG forum) and get feedback.

The other kindof-common problem, can be the evaporator sensor, which can give false readings to the system. Fortunately this sensor is realtively easy and affordable to replace.

I am not saying that could be a problem for you, post your current readings and let others comment.

Keep the beat !
 

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I would recommend you post the current AC values in the W210 forum (rather than the AMG forum) and get feedback.

The other kind of-common problem, can be the evaporator sensor, which can give false readings to the system. Fortunately this sensor is relatively easy and affordable to replace.

I am not saying that could be a problem for you, post your current readings and let others comment.

Keep the beat !
I'm thinking you may be right. For value #5 I get 129, which I understand is a un plausible reading. I think it should be in the 40-50 range. Thanks for the tip. :thumbsup:

DL
 

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Thanks for this info... It worked once about 5 months ago, but now I can't get the "d and FF" to show up and the ec light won't go off. Any advice?
 

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On my last road trip my AC compressor shut down (2000 W210 – E55) and the EC light became stuck in the on position. I searched many threads and even spoke to my local Indy Benz tech who told me I would have to bring the car to a MB tech who can clear the codes. Many posts I found confirmed this, saying you can’t clear the codes without hooking up to the DAS/STAR system. This in fact is NOT true.

After reading my codes I realized the system shut off the compressor due to low refrigerant pressure. When refrigerant pressure reaches about 8-7 bar or lower the compressor automatically shuts itself down, therefore making it impossible to recharge since the compressor will not pull in 134a. Once I cleared codes (easily), I was able to hook up a can of 134a to the low side line and charge the system successfully. If you have the same problem and no leaks (or very slow) you should be able to rectify this with a $30 can of 134a and some simple button pushing. The following menus should help you diagnose what is wrong with your system. I am not a MB tech nor do I profess to be one so I need to throw in the disclaimer – proceed with caution and at your own risk. I have made every attempt to compile clear and accurate info to help anyone else out that has gone through the same issue I have or other AC issues.

RETRIEVE DATA:

Turn on ignition (run car)
Put both sides Temp settings at 72
Push and hold “REST” button till you get a 1 in the left side
Push the left “AUTO” button to scroll forward and right auto button to scroll back.
Let the car run 3 minutes before pulling data to ensure more accurate data
For AC diagnosis you only need to be concerned about codes 1 through 8

Code 1 = Inside Temp
Code 2 = Outside Temp
Code 3 = Left Core Temp
Code 4 = Right Core Temp
Code 6 = Coolant Temp
Code 7 = Refrigerant Pressure (This is the important one)
Code 8 = Refrigerant Temp


PULLING FAULT CODES

Switch ignition on
Set left AC/heater temperature control to HI
Set right AC/heater temperature to LO
Depress REST and EC switches simultaneously within 20 seconds of turning ignition on
Hold REST and EC switches for more than 5 seconds
Air recirculation lamp flashes
Depress right AUTO switch repeatedly. Note trouble codes
FF is not a code

What the codes mean:
003 B1226 In-car temperature sensor with blower
005 B1228 Heater output temperature sensor
006 B1229 " " "
007 B1230 AC evaporator temperature sensor
008 B1231 Engine coolant temperature (ECT) sensor
009 B1232 AC refrigerant pressure sensor
010 B1233 AC refrigerant temperature sensor
011 B1234 AC sunlight sensor
012 B1235 Heater intake air purity sensor
013 B1241 AC refrig pressure sensor, AC temp pressure sensor refrigerant level
014 B1416 Engine coolant pump motor
019 B1417 Engine coolant heater regulator valve LH
020 B1418 " " RH
021 B1419 AC compressor clutch
022 B1420 Idle speed increase
023 B1421 Engine coolant blower motor control module
024 B1422 Serial interface K1
025 B1423 AC heater valve block
026 B1424 AC heater air intake filter actuator
027 B1425 " "
029 B1429 Serial interface K2


RESETTING FAULT CODES:

In fault code mode press both “AUTO” switches simultaneously for more than 5 seconds (after last trouble code is displayed)
Once codes are cleared you will see display change to "d and FF"
Switch ignition OFF – All Codes are erased


REFILLING SYSTEM:

Purchase a larger refill can of 134a with a gauge on it so you can read the low side pressure – helps as a guide to filling the system to the correct level. The instructions on the can will tell you what pressure to fill based on the ambient temp. You can find this refill can at any Walmart/Target/Auto Store for $20-$30. Make sure you purge the can before you fill:


Shake can
Squirt a very small amount of refrigerant to purge air out of the hose – you don’t want to introduce any air to your system.
Start car
Connect to low side port (drivers side left of engine mid bay with plastic black cap on it - unscrew)
Turn off EC button (light goes out and compressor goes on)
Read the PSI gauge on the can filler (should be low) around 20 psi or less
Pull trigger while gradually shaking the can and holding it upside down until it reaches instructed pressure depending on Ambient temp.
Once system is recharged it should be blowing cold air
Follow up by reading Code 7 – mine was originally 7 bar and became 17 bar after recharge. Also make note of the recharged bar pressure(17) – you can periodically check code 7 to make sure the system is holding the refrigerant pressure – if it decreases over time you have a slow leak and need to address it.

Hope this helps and good luck!
Will this method wok on a 93 400 SEL. I have used the diagnostic REST buttons and pressure is zero. Mine does not go into EC mode but everything else is the same. I have reset codes from other things in the past . I did not look for codes , but that will not be a problem for me .

The question is can I do this by myself ? I am handy but not very experienced . I have done some diagnostic work on car and pulled Fuel Injection covers etc and reinstalled plus a bit more. Got down as far as plug wires suppressors etc .

How would you rate the expertise necessary to do this? Can I do any damage ?
 
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