C230 A/C Diagnostic display (Climate control)--How to use - Page 3 - PeachParts Mercedes-Benz Forum

neznaika · #31 07-09-2007, 01:01 AM

I just bought this 1998 MB C280. 87k, had no problems driving it home for 1,500 miles in two days. After getting home, on the next day the A/C compressor would try to come on, but would shut off after 2-3 seconds (observed) Did this routine non-stop. It was 98-100 degrees outside. A/C worked, but since the compressor wasn't allowed to run properly, the air was just cool. Afraid of damage, I drove in EC mode. HOT...

When temps fell to higher 80s tonight, I tried tunning it again. The compressor is allowed to run and the A/C and climate control are running fine... BUT both of the condenser fans are running non-stop at max rpms. Doesn't matter if I drive or idle. I can't afford dealer, since I just bought the car. Please help! I found your thread VERY helpfull, but few numbers from Actual Values didn't match with mine. Evap temp is 38F. Not sure exactly what other numbers mean. Anyone has meanings for ALL of those Values? I've also found and cleared the following error codes: 232, 416, 417, 419. They were in the occasional category. Please help me figure out what's going on. Fans should not stay on like that. What the heck are they trying to cool??? My coolant temp is just fine.

SAVVY TOO · #32 07-25-2007, 05:15 PM

I have a c220 that is doing the same thing but it is hardly even blowing air out whats with that?

dondean · #33 07-25-2007, 06:11 PM

My 97 C280's AC had the same problem. I replaced evaporator temp. sensor, located above gas pedal. My AC works like new now. When it was bad the code 5 showed intermittently between CLS and 144. The good one showed 34F. In my opinion, you just go ahead to shoot evaporator temp. sensor. It will cost you $40s online part store, $70s in dealer part.

neznaika · #34 07-28-2007, 11:18 AM

Quote:

Originally Posted by dondean

When it was bad the code 5 showed intermittently between CLS and 144. The good one showed 34F. In my opinion, you just go ahead to shoot evaporator temp. sensor.

I wish it were that simple... My sensor shows normal temp 33-35F. I suspect a condenser sensor, if there is one. Or pressure sensor. Does anyone know if there are sensors on the compressor itself??? I notieced that my coolant pump, which is right above it, was slowly leaking for a long time. Could some sensor on the compressor have rusted?

97'C280 · #35 07-29-2007, 12:20 PM

1997 C280 and here's what I got by following the steps in this thread...car "off", ignition "on" :

1. - 84 degrees F
2. - 87 degrees F
3. - 78 degrees F
5. - 78 degrees F
6. - 89 degrees F
7. - 6 degrees 3
8. -84 degrees F
9. - 33 degrees F
10. -12*5
20. - 000
21. - 000
22. - 000
23. - 000
24. - 12*3
40. -03
42.- 02
43. - 6C
50. - 77 degrees F
51. - 65 degrees F
52. - 50 degrees F
54. - OFF

continuous codes - none - end
intermittent codes - 41.6, 41.7, 41.9, 42.1 - end

I will go out here in a second and clear the intermittent codes and see what happens but I'm guessing it's the evap sensor and low refrigerant, right?

somebody PLEASE answer this for me so I can stop sweating on my leather seats..I'm in Texas for crying out loud.

any info is appreciated.

anikon · #36 08-05-2007, 05:23 PM

I have a problem with my aux fans and CCU. Please see http://www.mbworld.org/forums/newreply.php?do=postreply&t=203952

Thanks

Basstrip · #37 12-26-2008, 03:28 AM

I have a 92 300SD and the driver side a/c control unit display is not responding. When I turn the knob allaway cold the screen reads 54F then went I move the tempeture knob the screen will read HI allaway. the passenger side is reading fine tempeture seeting. Does any body knows whats going on or how I can trouble shoot ACC unit

brookspw · #38 08-15-2009, 01:55 PM

Quote:

Originally Posted by JCE

This is what David C Klasse worked out for his 95 C280, and it seems to be the same for my 98 C230, so maybe it works for you:

With ignition in on position, turn climate controls on, then press and hold REST for 5 or so seconds, or until you see an 01 flash then another number will flash (inside temp), then back to one, use the arrow up (defrost) and arrow down (feet) to scroll up and down through the codes.

1. In-car termperature sensor (with aspirator blower)
2. Outside temperature sensor
3. Heater core temperature sensor
5. Evaporator temperature sensor
6. ECT sensor (Coolant temp.), e.g. 12*5 = 125C
7. Refrigerant pressure in bar, e.g. 12*8 = 12.8 bar
8. Blower control voltage, e.g. 16*5 = 1.65 volts
9. Software status of A/C pushbutton control module
15. Selected in-car temperature
20. Version code
21. Engine Speed (RPM), e.g. 6*0 = 600 rpm
22. Terminal 58d (Bat. Volt.), e.g. 99.0 = 99% of voltage
23. Vehicle speed (Kilometers Per Hour)
50. Not used – 00
51. Number of current slip recognition (poly-V-belt)
52. Number of stored slip recognitions (poly-V-belt)

My #7 reading is 19*8--20*5. I am assuming this is too high. If so, this is keeping my compressor from turning on and I need to remove 134a from the system?

Matt L · #39 08-15-2009, 03:52 PM

Quote:

Originally Posted by brookspw

My #7 reading is 19*8--20*5. I am assuming this is too high. If so, this is keeping my compressor from turning on and I need to remove 134a from the system?

With the compressor off? If so, it might prevent the compressor from starting as it is illogical. It would point to a bad pressure temperature sending unit (located on the dryer).

Don't just remove some 134a. Rather, if you're unsure of the fill quantity, recover all of the 134a and recharge by weight to factory specifications.

brookspw · #40 08-22-2009, 05:04 PM

Quote:

Originally Posted by brookspw

My #7 reading is 19*8--20*5. I am assuming this is too high. If so, this is keeping my compressor from turning on and I need to remove 134a from the system?

Ok, after further review -- I'm actually more confused.

If I run the diagnostic at idle, I get about 21*0.
If I run it sitting still, but RPM at 3,000, I get about 23-24.
In neither of the above do I get very cold air at all.

If I run the diagnostic while riding down the road, even if only at 30-40 MPH and maybe just 1,200 rpm...the #7 reading is about 7*5, and I get pretty cold air. Not as cold as I should be but around 50.

I'm thinking there may be more of a sensor/switch/elec issue than a freon thing.

Matt L · #41 08-22-2009, 06:24 PM

It could be condenser airflow. Check for an operational mechanical fan clutch (if equipped) and electric fan. If those are good, check for debris in the air path through the condenser and radiator.

Be sure that the temperature is set to LO when you measure the vents (set it before entering diagnostic mode). Otherwise you may be getting some reheating of the air.

brookspw · #42 08-23-2009, 04:25 PM

Quote:

Originally Posted by Matt L

It could be condenser airflow. Check for an operational mechanical fan clutch (if equipped) and electric fan. If those are good, check for debris in the air path through the condenser and radiator.

Be sure that the temperature is set to LO when you measure the vents (set it before entering diagnostic mode). Otherwise you may be getting some reheating of the air.

Educate me -- tell me how you deduce this from my symptoms. I'm just trying to follow along. Seems to me...the pressure would get higher at 3k RPM not lower.

brookspw · #43 09-10-2009, 10:43 AM

Update:

1 -- A/C works fine when outside temp is 80 or less. Works on/off when 80-90. Won't come on at all if over 90.

2 -- Diagnostic shows, at highway speed, pressure bars between 11-16 when compressor is running but 23-28 when compressor is off.

Any helpful analysis is appreciated.

Thanks.

Matt L · #44 09-10-2009, 10:53 AM

23-28 with the compressor off is illogical. Compare this to the actual high-side pressure. You may have a bad pressure sensor.

Or you have a severely overcharged system which also has a restriction at the condenser or dryer. This will cause the pressure to drop when the compressor engages. But it will also likely blow off refrigerant from the compressor pop-off valve.

Without knowing the pressure at the high-side service port, you are guessing.

Brian McL · #45 12-12-2009, 06:59 PM

This is a 1997 W210 E320.
I have #7 reading as 00 ( I think refrig. press.) with engine on or off. Compressor will not turn on. If there was a leak in the evaporator (like my W124) wouldn't the pressure read at last 1 bar, atmosphere?
I'm hoping that the sensor has failed.....anyway to test it?
Also noticed that #10 (fan voltage ?) reading changes as the fan speed selector is changed to hight setting butthe fan speed doesn't change from low, or about 2.3 V.
Does this mean the fan speed resistor is OK or not OK ?
Also, where can I get a list of what all the other readouts refer to and the normal range for each for this car?
There seem to be differences between car models for the same year.
Nice having all the numbers but if I can't relate them to anything it's still all a mystery.
I have alldatadiy but they don't even describe the test proceedure.
Thanks