AC Problem - refrigerant pressure
06-25-2009, 08:04 PM
#27
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2005 C240 4MATIC, 2010 ML350
I had similar symptoms. In my case, it was two things:
1) The stepper motor was faulty, and was not able to put itself into the proper position to feed a full cooled air mixture to the cabin. This was diagnosed by checking the positions on the SDS system. It was blatantly obvious from the positions that were being returned to the tech.
2) The wire harness for the climate control was frayed at the body (I kid you not)
The stepper motor was replaced first, which got my air cold. However, I was still suffering from intermittent shutoffs. The tech found situation number two by checking for voltage errors at each point in the system. Errors were being returned by the climate control panel in the center console, so they traced the harness back and found it frayed on the body - they replaced it and I haven't had a shutoff since.
I'm not sure if these two issues are part of your problem...but it might not hurt checking.
The first thing the SA had the tech's do was check refrigerant levels - I was at a full charge. That's when they went to SDS to look and see what the car was saying.
You might want to have them check for voltage errors. Or find another dealer.
1) The stepper motor was faulty, and was not able to put itself into the proper position to feed a full cooled air mixture to the cabin. This was diagnosed by checking the positions on the SDS system. It was blatantly obvious from the positions that were being returned to the tech.
2) The wire harness for the climate control was frayed at the body (I kid you not)
The stepper motor was replaced first, which got my air cold. However, I was still suffering from intermittent shutoffs. The tech found situation number two by checking for voltage errors at each point in the system. Errors were being returned by the climate control panel in the center console, so they traced the harness back and found it frayed on the body - they replaced it and I haven't had a shutoff since.
I'm not sure if these two issues are part of your problem...but it might not hurt checking.
The first thing the SA had the tech's do was check refrigerant levels - I was at a full charge. That's when they went to SDS to look and see what the car was saying.
You might want to have them check for voltage errors. Or find another dealer.
06-25-2009, 09:43 PM
#28
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1999 Civic Hatchback, 2002 c240, 2003 CLK 500
thanks, they told me that there were no codes, i will ask about the voltage errors tomorrow, they have had my car for a week tomorrow.. what dealer did u go to?
my car is at Phoenix Motors Arrowhead..
my car is at Phoenix Motors Arrowhead..
06-26-2009, 12:35 AM
#29
Super Moderator
06-26-2009, 12:38 AM
#30
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I had similar symptoms. In my case, it was two things:
1) The stepper motor was faulty, and was not able to put itself into the proper position to feed a full cooled air mixture to the cabin. This was diagnosed by checking the positions on the SDS system. It was blatantly obvious from the positions that were being returned to the tech.
2) The wire harness for the climate control was frayed at the body (I kid you not)
The stepper motor was replaced first, which got my air cold. However, I was still suffering from intermittent shutoffs. The tech found situation number two by checking for voltage errors at each point in the system. Errors were being returned by the climate control panel in the center console, so they traced the harness back and found it frayed on the body - they replaced it and I haven't had a shutoff since.
I'm not sure if these two issues are part of your problem...but it might not hurt checking.
The first thing the SA had the tech's do was check refrigerant levels - I was at a full charge. That's when they went to SDS to look and see what the car was saying.
You might want to have them check for voltage errors. Or find another dealer.
1) The stepper motor was faulty, and was not able to put itself into the proper position to feed a full cooled air mixture to the cabin. This was diagnosed by checking the positions on the SDS system. It was blatantly obvious from the positions that were being returned to the tech.
2) The wire harness for the climate control was frayed at the body (I kid you not)
The stepper motor was replaced first, which got my air cold. However, I was still suffering from intermittent shutoffs. The tech found situation number two by checking for voltage errors at each point in the system. Errors were being returned by the climate control panel in the center console, so they traced the harness back and found it frayed on the body - they replaced it and I haven't had a shutoff since.
I'm not sure if these two issues are part of your problem...but it might not hurt checking.
The first thing the SA had the tech's do was check refrigerant levels - I was at a full charge. That's when they went to SDS to look and see what the car was saying.
You might want to have them check for voltage errors. Or find another dealer.
06-26-2009, 10:31 AM
#31
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2005 C240 4MATIC, 2010 ML350
I bought my car and get it serviced at Schumacher. They are extremely competent there. Very friendly. Not always the cheapest, but they do the job right. I work with Erik Bobesku. Occasionally they have service coupons as well.
06-26-2009, 10:33 AM
#32
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2005 C240 4MATIC, 2010 ML350
Yea, my SA said that the tech found it as he was tracing everything back checking components. That's why they were getting the voltage errors - makes total sense when you think about it - especially because it was so random. A failed component would give a fairly consistent result, but a frayed harness will not create a short circuit consistently.
06-27-2009, 01:28 AM
#33
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1999 Civic Hatchback, 2002 c240, 2003 CLK 500
i ok'd them to change out the compressor
also a note to anyone who is not hearing the auxiliary fans soaring at top speed.. a faulty fan could cause your compressor wear and tear..
also a note to anyone who is not hearing the auxiliary fans soaring at top speed.. a faulty fan could cause your compressor wear and tear..
06-27-2009, 09:58 AM
#34
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What constitutes a faulty fan? More likely a faulty fan controller. If the fan works it should attain max RPM unless you have a burnt out winding in the motor.
06-28-2009, 06:50 PM
#35
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i have the same problem with bbrain. cold when running and tends to heat up when standing still.. also sometimes (i always use the auto button) the ac turns off by itself. i press auto again to turn it on but after 10 secs it shuts off again. but sometimes just stays on. i thought it was a temp thing like the car feels like its cold enough thats why it turns off.. is this an issue i should be concerned with? or is it normal?
06-30-2009, 09:37 PM
#36
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1999 Civic Hatchback, 2002 c240, 2003 CLK 500
thanks to all that helped, compressor is changed and i was able to get them to put the original aux fans (which had no problems thanks glyn) back in .
upsides are cold air and had a c350 for about 2 weeks. heh
upsides are cold air and had a c350 for about 2 weeks. heh
07-01-2009, 07:09 AM
#37
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Good News - I thought there was nothing wrong with the fans - really - they either work or they don't. Hope you saved a few bucks.
07-25-2009, 10:43 PM
#38
Newbie
So my AC compressor was toast.
Replaced it with one from 2007 MB C240, yes fit perfect and works perfect too..
My AC off switch was stuck on Off mode, well after filling up the Freon and manually jumping the compressor, the car cooled, fan and all functioned, I could not figure out what was up, I had and extra AC control switch (AC control unit inside the car) and as soon as I switched the part my AC was fully operational, so it seems that the issue had nothing to do with Low or High pressure switches, but somehow this unit tripped and somehow stored the code?? I am not sure, so hope this helps a few who have alluded to this same problem, see if you can replace that AC control and you might be able to get your compressor to kick on again.
Replaced it with one from 2007 MB C240, yes fit perfect and works perfect too..
My AC off switch was stuck on Off mode, well after filling up the Freon and manually jumping the compressor, the car cooled, fan and all functioned, I could not figure out what was up, I had and extra AC control switch (AC control unit inside the car) and as soon as I switched the part my AC was fully operational, so it seems that the issue had nothing to do with Low or High pressure switches, but somehow this unit tripped and somehow stored the code?? I am not sure, so hope this helps a few who have alluded to this same problem, see if you can replace that AC control and you might be able to get your compressor to kick on again.
07-26-2009, 07:09 AM
#39
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Just remember that early models up to sometime in 2004 in most markets had a non intuitive push for aircon OFF switch - changed later to a push for aircon ON switch. This can cause confusion.
08-05-2009, 10:22 PM
#40
what is the optimum refrigerant pressure and at what pressure should the refrigerant be replaced? i've been using that nifty A/C menu and I believe option 9 reads out refrigerant pressure if i remember correctly.
08-06-2009, 12:22 AM
#41
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also i havent done anything to fix my A/C. new observation: when i use manual controls, when i max out the fan doesnt get cold. but if i leave the knob 3/4 its ice cold..
so if i use AUTO it automatically blasts max air hence the hot air.. anyone with a similar observation?
08-07-2009, 03:45 AM
#42
11-18-2018, 09:11 PM
#43
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VW
I have similar problem. 08 e350-fans running at 20% and ac compressor at 70%. Replaced compressor and expansion valve and still will go only to 70% power on the compressor.Did they mention anything else?
11-19-2018, 01:48 AM
#44
The dude cycle you're seeing is for the PWM valve which controls the compressor. 70% is the max duty cycle of the valve not the compressors. That's normal behavior.
