Babaloo

I spent a good deal of time carefully researching the many threads and links regarding AC issues. My 2000 CLK430 convertible is a great car, low mileage, but the heating and cooling are wildly erratic. I'd appreciate your input on what I've found:

First I cleaned the air cleaner. Then I ran the list of Fault Codes. There were no error codes, but FF appeared.

Then I ran the AC Diagnostic with the engine off and cold. I warmed up the car and reran them. The weather here is chilly. I can tell you all the values if you like, but here are the few that I think might be trying to tell me something:
08 - Freon temp was 55 at first, then 104 with the engine warmed up, and it dropped to 76 while I was driving around.
09 - This was 0 with the engine cold, then 12 with the engine warm, and 17 driving around.
20 was 0. Is this ever supposed to be 0?

Finally I ran the Vent test, and here I got results unlike anything I expected. In all 15 codes, in the Lo setting, the left and right vents were always on.
0, Hi - AC came out both center dash flaps, heat coming out everywhere else.
1 - behaved just like 0.
2, Hi - both center vents are cold, heat coming out side vents
3, Hi - both center vents are mixed hot and cold air, side vents are hot
4, Hi - flow is reduced in the center vents, sides are hot with more air flow
5 thru 8, Hi - defrosters seem OK, but side vents are always on
9 and 10 - OK
11 thru 14, Hi - floor vents OK, but side vents always on
15, Lo - side vents and defrosters on, Hi - everything on except the defrosters.

I look forward to your diagnostic genius!

stim141

You need to provide the first 7 sensors to determine anything. Freon temp - not such a big deal but what is a big deal is the pressure reading from #7. The sensor for the evaporator is also key to determine what is going on with the system. Think its number 5. The pressure sensor should report in the 10-13 range when temps are above 70F outside anything colder has an effect on the gas/pressure and you'll get readings of in the 6-7 to 10 when its working. It may drop as low as 3-5 which is also pretty normal when outside temps are very low.

Babaloo

Thanks for the help, and I appreciate any thoughts you have on these numbers. I've put two values in parentheses - first is the engine off and cold, outside temp is cold. The second number is engine warm and running.
1 (58, 71) in-car temp seems right
2 (43, 46) bumper temp rose with the car sitting still while running, so this seems right
3 (69, 101) left core heater, and I don't know if this is right?
4 (69, 103) right core heater, same question
5 (46, 38) evap sensor temp seems like what I read it should be - any thoughts?
6 (88, 185) engine temp seems right
7 (4, 10) freon pressure went up to 13 driving around, seems like what I read it should be?
8 (55, 76) freon temp went up to 104 while I was sitting idling. Thoughts?
9 (0, 17) also read 12 when idling. I thought this was always supposed to be zero?
10 (6, 6) blower voltage good
20 (0, 0) radiator electric fan current - I suppose I should check when the car is really hot?
21 to 43 seem unimportant for now.

So what do you think? Since there are no error codes, and with these values, I imagine I should replace the blower motor regulator. Anything else look odd to you?

Babaloo

I think the vent test was pretty weird, unless the "Individual Flap Test" table I have is for a different car. Any guesses about whether the vacuum lines are wonky, or does this point toward something else? Thanks again for any ideas

Babaloo

Stim141, thanks for the input. I think 5 and 7 look right, but what about 8?

Anyone have comments on my vent test results? The Blower Motor Regulator doesn't affect flap positions, does it?

Babaloo

Come on now, you're leaving me talking to myself. Surely somebody out there loves their air conditioner and can give me thoughts on these test results? I'm going to hold my breath until you answer....

Ti8kitti

0

stim141

Its too cold to determine if the AC system is working properly! You are going to have to wait unfortunately until outside temps get in the 70's

Your readings seem ok - with ambient temps in the 40-50 range evap temps in the 38 range is correct. The only thing though is when temps go up past 70 the evap temps
should stay the same if the system is operating fine - if its not the evap temps will creap up past 40 which it shouldn't. According to my AC guy its very hard when outside temps are this low to do a proper fill and diag. They really like to really test systems when outside temps are hot. The good thing is that your compressor is working - how well is still yet to be determined.

The only problem I can see is the heater core values - they shouldn't be that high which means that the duovalve isn't closing. You should move your temp control set values down to low to see if those numbers drop. They should get to outside air temps if the valve is closing fully - meaning no hot coolant is going to the heater core. If not I'd clean it or replace the valve which is easy and the DIY is on the forum.

I have a problem with my system - its taking too long to bring down the evap temp. They think its a fill problem but will only refill it when outside temps go up past 70+. Last year during the heat of the summer which was in the high 90's to 101F my system was running perfectly - got evap temps during normal operation as low a 38 and when the fan was on three bars almost down to 36F which is excellent. My current bar (7) reading is about 14 when the car is just sitting at idle but the evap temp only goes to about 40. I got one of those dye detect kits which shows the leaking dye with a Uv light - couldn't find anything in the engine compartment except some trace around the receiver/drier so it could mean a slow leak or some leaking from expansion/contraction - maybe. Didn't test it in the car at the evaporator which is next. That I hope isn't the problem because the entire dash has to come out!

Ac systems like ours are a major pain to find problems esp when you have the digital climate control system. Unlike a car that just has an AC on button which basically turns on the compressor and relies on fill pressure and fans to regulate it ours uses a variety of sensors/fans to regulate the compressor and the fans. If one is out or off a proper fill is the first thing that should be done - evac the entire system, pull a vacuum then fill to spec by weight/volume. This is dependent on ambient temps and humidity. If the fill is perfect then if it isn't working properly they have to go though each sensor to determine if they are working - then they replace the entire climate controller/computer ($$$). A few years ago my dealer had my car for nearly a month tracking down a fan controller problem - fortunately it was under an extended warranty.

Getting someone to get a perfect fill is CRUCIAL to the operation of the system - if its too low - slow or no cooling. If its too high then the compressor is working too hard and can't compress the gas so little to no cooling as well.

Babaloo

Great help, thanks for the input. Waiting for warm weather in Seattle will take awhile, but when it happens I'll be ready to retest.

riveroftears

Ok
CLK430 with 42k miles
I would appreciate any help with this
codes are
1 86
2 144
3 65
4 67
5 72
6 194
7 12
8 13
and i do have a code error EB1 241 and E FF
i went to a local mechanic and he said the feron level is reading 50 which is quite normal and it does not need feron but refered me to the mercedes dealer and i really do not want to go there , can any body help

lisaclk320

I have a 2000 CLK320 and was told on Saturday that my compressor is dead. How do I run the code test for this ? I want to make sure this is the problem before I spend money.

stim141

To RIVEROFTEARS - try resetting/clearing the AC codes. Your 7 pressure seems fine and the compressor should start up.

1. Turn car off
2. Key in second position. Put the right temp to low and the left to HI. Turn off
3. Turn to 2nd position again - within 10 seconds press and hold the ResT/EC button simulataneously

4. You are in the diag of the climate control, press the right AUTO to bring the code up and then press and hold the LEFT AND RIGHT AUTO BUTTONS until you see a DD or dd, scroll again with the right AUTO until FF or you see another code, clear it.

5. TURN OFF then restart - it should start up the compressor once the code is cleared. Drive around and then do the diag again to see if you get another code.