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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!


Great idea. I have a 93 400 SEL that we replaces evaporator drier etc on 2004 . Last summer I ran low on R134a and my Indy put some in but his tank ran dry. Approx 6 BAR using the diagnostics on board display. That lasted till about a month ago .

My Indy does not has the large tank to fill it properly yet .He is waiting till it gets warmer to order it. I am impatient and will be going away for a few months and dont want to come home mid July to sweltering heat and no a/c.
If I were to buy the one with Uv and convince him to install it as a stop gap measure, what brand would you recommend. Anyone feel free to jump in here

Thanks
 

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Thank ya! thank ya!

Followed your directions on my 02 e55, cleared codes, fired up ac full blast, added one can of coolant and another of coolant plus leak sealer, now I got icy cold ac! Thanks for the info! Works like a charm (for now ;) )
Next mission: Cabin air filters!
 

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My EC came on on my 1998 SL500 tried to get compressor to engage after adding 10 oz freon. No go. Kept trying to reset EC by pushing, finally when I pushed and held it light up "SMOG" and after holding about 10 seconds EC went out and compressor came on and AC is working. I did not know about all the coding at the time and may have pushes a bunch of other buttons before, but this finally worked. I had also disconnected my battery a couple of times, because on my 1996 Cadillac Seville SLS that is what had to be done to reset compressor when freon got low. However that didn't fix it either, only the hold EC did it. Hope this helps someone. I enjoy all the advise and knowledge that blesses this site.
 

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AC Still Blowing Warm Air

It has been a while since I have been on the forum. I've been pretty lucky not having a lot of trouble with my car (2001 E320 Sport). But the other day, the AC, all of the sudden, started blowing warm air. I found this post and tried it last night.

Code 7 was 7 and the error code was B1234 AC Sunlight Sensor. (I didn't get any others.) I bought some 134a refrigerant and tried to charge the system, but the pressure gauge on the can read 110psi and was in the warning zone. The compressor is turning, AC is turned to LO on both sides with the recirc button pushed. The system will not accept the 134a.

Any ideas?

Thanks.
 

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Are you sure your compressor is actually engaging? The pulley spins, but the clutch connects the compressor to the pulley to actually turn the compressor.

In my case just last week, my compressor had failed and broken and had to be replaced. My car would not accept refrigerant and I think this was since the compressor was not actually engaging and the system pressure was the same throughout (low side reads high).
 

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I just checked to make sure the compressor was engaging. I turned the air conditioning on and observed the compressor clutch had engaged and was turning. Just to verify, I had someone push the EC switch and observed the clutch disengaged.

I think the real question is now is why does the diagnostic say 7 bars pressure and the 134a can says 110? I did try to put some refrigerant in this morning, but chickened out because of the pressure indicated on the 134a can. The diagnostic now says code 7 is 8 Bars.

Also, I banged on the duovalve with the end of a screwdriver as recommended by ohlord - no help. Is it possible that I still need to take it apart and clean and replace?
 

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7 bars is about 110 PSI. 1 bar = 14 psi.

Your compressor is not working. Otherwise your lowside would be around 2-4 bar and your highside would be as high as 17. Your system appears to be like mine was without compression, all even at 7 bar.

My bet it that your compressor is not compressing but you do have refrigerant.
 

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Thank you. Sincerely!
The Poly-V belt broke during a recent road trip in my 2001 E320 wagon. The good news: The parts were in stock and less than $80 at Pep Boys. Real parts, too! USA made belt. Idle pulley from Germany.
The bad news: I was entirely at a loss how to get my a/c to work! Worse yet, the "import specialist" I took it to informed me that he didn't have the machine to read the code for my a/c, after I explained that the a/c stopped working and the EC light came on during the same incident. He was kind enough to check all the fuses, unplug the battery, and not charge me for the service because he didn't fix anything, but still... um.... specialist? How can a "specialist" not know that the a/c has its own readout? Wonder what else he doesn't know.
And, here I am. Thanking you for saving me a trip to the dealer! This worked perfectly.
Naturally, the system threw EVERY code (including several not listed in your original post.) The reset was super-simple and my a/c is working perfectly once again.
Thank you! Thank you! Thank you!
 

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Hey guys, getting a code I'm unable to find info on.

Replaced compressor, drier, and expansion valve as my compressor had seized. Pulled vaccum, went to shoot gas in and the w210 is not taking it. When I run engine and check codes, I get b1235 (heater intake impurity) and b1416 (engine coolant pump)

My ec light is off, but the compressor is not running.

Any ideas?
 

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Hey guys, getting a code I'm unable to find info on.

Replaced compressor, drier, and expansion valve as my compressor had seized. Pulled vaccum, went to shoot gas in and the w210 is not taking it. When I run engine and check codes, I get b1235 (heater intake impurity) and b1416 (engine coolant pump)

My ec light is off, but the compressor is not running.

Any ideas?
Post this in the regular W210 forum. You will get more help there
 
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