ballot

Hi guys,

I'm having a problem with the EC light being stuck on all the time preventing me from using the A/C. I read thru all the posts that talk about this problem and they all focus on recharging the A/C (being low on freon). I recharged the A/C and that didn't fix the problem. The light is still stuck on. I think the problem might be related to a sensor but I'm not sure. I was able to obtain the A/C sensor values when holding the EC and REST button for ~10 seconds. The sensor values are as follows:

Sensor Value
01 87
02 80
03 93
04 93
05 93
06 201
07 7
08 91
09 0
10 1
11 1
12 1

The only two sensor values that i don't like is sensor #6 (value is 201) and sensor #7 (value is 7). Does anyone know what these sensors are? Is any of them related to the refrigerant pressure sensor?

Your help is greatly appreciated.

splinter

Welcome to the forum.

Sorry to see you are experiencing HVAC problems. If you're in the northern hemisphere, at least you have a few months to get things straightened away before you need the AC, although its dehumidifying properties provide a beneficial safety effect year ‘round...

When you replenished the R13a, how much did the system require? Did you DIY, and/or do you know its low & high side (gauge) pressures?

Here are the menu’s indicators and units of measure, as pilfered from other MBW members:

01 In-car temperature sensor.
02 Outside temperature sensor.
03 Heater core temp, left.
04 Heater core temp, right.
05 Evaporator temperature sensor.
06 Engine coolant temperature.
07 Refrigerant pressure in bar (e.g. '4' is 4 bar).
08 Refrigerant temperature.
09 Not used.
10 Heater blower control voltage (normal 08-6.0, meaning .8 to 6 volts).
11 Emissions sensor voltage (to detect atmospheric gases and recirculate interior air).
12 Sun sensor voltage (to shift airflow in car).
20 Control current for auxiliary fan (electric fan on radiator, given in milliamps or mA).
21 Engine speed (x100).
22 Road speed (km/h or mph depending on installation).
23 Battery voltage at terminal 58d (as a percentage of total voltage, e.g. 99.0 = 99%).
24 Battery voltage (e.g. 12.8 = 12.8V).
40 Climate control software version.
41 Climate control hardware version.

ballot

Thanks Splinter for your speedy reply,

My friend actually helped me in recharging the system (he has his own garage but doesn't have the DAS STAR tool to diagnose the MB). I asked him to recharge the high and low gauges to 1.7 lbs (which is the recommended number). He had to vacuum the A/C system first prior to recharging. He told me that there was some freon left, but he still did it anyway. I think there is something else that's wrong with the A/C.

Thanks a lot for posting the measure units. this is a great reference. On sensor #7 (Refrigerant pressure ), I'm assuming that the value 7 means 1.07. Is this number within specification? Also, is sensor #6 within specifications?

Thanks.

T.O_c240

Hey i had a similar problem when i bought my car....EC light stuck on.

The place i bought the car from said it was prolly the EC button so a few weeks later they replaced the entire temperature/fan control unit on the dash and with the new one in it started blowin cold air in so problem solved.

Maybe if you find a used one or borrow one from a friend u can see if thats the problem

ballot

The car has 70kmiles on it. i don't understand how would the control unit break just like that. I think people are changing the control unit while in fact the control unit only requires a reset signal from the DAS software after fixing the root cause of the problem (eg. freon, sensor, compressor ..etc). i'm thinking of taking the car to the dealer in couple of weeks and have them scan it using the DAS software and tell me where the problem lies. I still don't know if sensors #6 and #7 are outputting values within specs.

ohlord

fine it is your engine coolant temp,corresponds to the reading on the dash display,7 is pressure usually reads variable based on demand from 7-20.
If the light wont go out,you can not properly run the diagnostics,run the error codes and post them.
the only values you need for the a/c are 1-8
Your compressor is not operating,you have a temp sensor or a pressure sensor,or low 134a.
go to this link run the error codes and lets see what's up.
http://www.eclassbenz.com/node/27
ohlord
and to the other member above when the problem is fixed the codes clear themselves and if not while in error mode you can reset them yourself,no need for the dealer or his das!

ballot

Thanks ohlord .

I actually know this link and i tried it, but the light still remains on. The values that i got were:

01 87
02 80
03 93
04 93
05 93
06 201
07 7
08 91

its now between the temp sensor and the pressure sensor ( i'm hoping its not the compressor). I know the pressure sensor is located under the radiator. Do you know where the temp sensor is located? Any idea how much these sensors cost?

SUNILP

the best way to diagnose the problem is using a star diagnose system or similar system that can scan for the code. Unless you do this, you will be spending unnecessary money in components that may not need replacement.

ballot

Just spoke with the dealer. It will cost me $60 to get the trouble code readout. Will go there next weekend to have it checked.

patrick_y

Come to think of it, the 2002 E320 in the garage had the same problem when the car was brand new. Took it into the dealership and had them fix it under warranty, apparently it was a broken switch.

ballot

So i took the car to the dealer and had them give me the readout of the DAS test log. I figured it could be worth the 60 bucks. The attachments are located under post #9 of the following link:

https://mbworld.org/forums/c-class-w203/216856-battery-problem.html

The dealer claimed that the refrigerant level is too low. My friend checked the vehicle today and recharged it with 1.7lbs (750 grams), but still no luck. The light remained stuck on. I think the problem is in one of the sensors (like the B12/2, but don't want to rush and buy it if i don't need it. Its costs ~ $100).

With the attached documents, would you be able to tell where the problem lies?

Thank you

ballot

Any idea guys?

ballot

do you think its the climate control module?

ballot

I changed the refrigerant pressure sensor and recharged the A/C system and the EC light is still ON . Also, the mechanic put die in the system and there was no leaks!!!. I don't really know what else to do . My car keeps on fogging up even in the winter. I don't know why the A/C is needed in the winter!!!!

I feel like burning this car now. I should go back to my Camry and have a piece of mind.