1997 W210 E320 Cliamte "P values" - PeachParts Mercedes-Benz Forum

Bigdaddybenz · #1 06-17-2006, 09:34 AM

Does anyone here have the original factory settings for the "P1, P2, etc" values that are set in the climate control unit?????

After an episode of my "EC" light being locked on, I followed the instructions on changing the values, thus turning it off.....Unfortunately for me, I suspect that I inadvertently changed one of the values that I shouldn't have because even though the "EC" light problem was corrected, I can no longer get the option for the "arrows" on the display to point to the vents. That option appears to have been deleted!!!

Is there a way to factory default these values????

Thanks in advance, guys!!!

Matt L · #2 06-17-2006, 10:37 AM

1. Numerical Value
00 Serial Interface K1
08 Serial Interface K1 and K2 (M.Y. 1997)
32 Auxiliary fan not available as of (M.Y. 1997)

2. Numerical Value
00 Engine version over CAN from instrument cluster (as of M.Y. 1997)
+08 Blower motor bar graph switched on by AUTO
+16 Refridgerant fill level check switched off
+128 SMOG display switched off

Bigdaddybenz · #3 06-17-2006, 11:26 AM

Thanks a lot MATT L!!!!

Just for the heck of it (and in the name of caution), I will post the current values that I pull out of the unit BEFORE I change any of them.....

Hopefully, you'll be around sooner or later to offer an opninion

Thanks again, friend!

Bigdaddybenz · #4 06-17-2006, 10:14 PM

Ok Matt and the rest of the forum elite,

When I follw this procedure---> """37/99-2 GROUP 83 - MODEL 210, CLIMATE CONTROL "EC" LAMP ON: *** UPDATE TO MB-NET MESSAGE NO. 220 DATED APRIL 16, 1999, DTB 17/99 ***: If you receive client complaints on model 210 of "the EC lamp on", please check the system according to the published diagnostic and service procedures. Check if the version coding is correct. Replace the refrigerant temperature sensor in every case. If the refrigerant quantity, temperature or pressure sensors are within the specified values, the low refrigerant level indication should be switched off via the HHT or via the on-board diagnostics (P2 value) as described below. Do not replace AAC push-button modules for this complaint.
Please note that "EC" lamp low refrigerant indication is a redundant feature. Disabling this feature does not compromise the safety of the AC system, because the AC compressor will switch off if low refrigerant (level) pressure is detected.
Switching of the "EC" lamp low refrigerant level detection via the AAC Push-button Control Module can be accomplished as follows:
Switch ignition to position 2.
Set the left temperature to "HI" and the right to "LO"
Switch the ignition off.
While holding the "REST" button, switch the ignition to pos. 2. On the left side of the display, "P1" will be blinking and on the right side, the version code is
displayed. Press the "EC" button, no change is needed for the P1 value.
Press the "EC" button again. "P2", will be blinking on the left side of the display and the value on the right side.
Record this value. Using the right side temperature (red) button add 16 to the displayed value.
Press the "EC" button to store the updated version code.
Turn the ignition off and on again. Reset the left and right side temperatures to 72?F (by pressing the red and blue buttons at the same time).
For warranty, please use Damage Code 83752 04.""""

The CCU will only allow me to set the left side "hi" and the right side "low" if I command the blower to engage, once that happens and I go through the rest of the procedure the following is what is displayed on the CCU's LCD display:

Left side= 1..................................Right side=32
Simultaneously I can see the "P-1" barely blinking in the background as if it were trying to display under the "1" (if I cut the blower off at this point ONLY the 1 is displayed).

Next, when I press the EC buttoin twice, the same thing happens except the "P-2" is barely flashing behind the 1.....The 1 on the left side and the 32 on the right side remain the same...

In both cases, the right temp switch does allow me to change the value of the numbers on the right side of the display.....

Somehow, I feel that I am missing a very basic step in this process that is not allowing me to check and/or change the values as required and posted above by Matt.

ANYONE willing to provide a bit of insight about this circumstance will be greatly appreciated!!!

btw, To further describe my earlier mentioned concern about not seeing the "horizontal arrows" available on the display......I now only have the option of an "up", "down" and "up & down together" options on the CCU's vent controls.......It appears that without the horizontal arrow my AC's ability to properly cool the cabin has been somewhat compromised.

I also ran the self diagnostics from Steve's impressive article and everything appears to be within the given parameters, I did see mention of #7 bar. pressure and though I have seen posts that stated it should be in the mid teens range, mine fluctuates between 13-14!!

Thanks guys!

Matt L · #5 06-17-2006, 10:27 PM

I have no idea what the P1 value 32, "Auxiliary fan not available" means. I assume that you still have one, as you really can't have an air-conditioned car without that, but perhaps it means that N22 no longer controls it.

As for engaging the blower, I also can't set the temperatures with the climate control turned off.

It doesn't sound like you're missing anything, but the flashing left-side display sounds odd. Since this started with a version code, perhaps that's the only problem here. Note that the instructions that you copied, saying to add 16, assumes that 16 was not previousely added. You need to break the number down into binary to see if 16 is present.

As for the high-side pressure, what's the vent temperature? If you're getting close to 40F at the left-side center vent (with the temperature setting below the actual inside temperature), you're fine. Unless the system is under load, you won't see high pressures. This assumes that your auxiliary fan works. If not, your high-side pressure will spike.

Bigdaddybenz · #6 06-17-2006, 10:39 PM

Hi Matt

There's a "1" displayed with "P-1" blinking lightly behind the "1" that is displayed on the leftside when the CCU is in this mode! Seems a bit unusual. Almost as if it were stuck in 2 different modes simultaneously..

I will follow your advice and attempt to break the rightside "32" value down into binary.

Orogainally, when the "EC" light became locked on, I knew that I must have had a low freon level in the system.....When I put the system into self-diagnostics mode, my #7 was coming in at 7bar, I added what had to be no more than roughly 3 ounces of R134 and it came in between 13-14 bar, though I have seen it dip down as low as 9 bar on hotter days (90 degrees).....I stopped adding refrigerant because I didn't like the minor noises that the compressor was statrting to make......I shut the car off, heard the freon equalize and then restarted the vehicle and turned on the AC.......The compressor was fine, and my left vents got a bit cooler but still no comparison to the right vents cooling capacities......and in no way as cool as they were originally

Matt L · #7 06-18-2006, 12:35 AM

32 is 2^5, i.e., one bit set in base-2.

I don't know that you needed to add any refridgerant. Perhaps it's now too full. You can remove some by chilling a can that isn't full and connecting it to the low-side connector, with the compressor (and engine) off.

A bowl of ice works well for this. Don't remove refridgerant too quickly or you'll also remove oil.

Bigdaddybenz · #8 06-18-2006, 10:09 AM

Hiya Matt!!!

I have a question regarding the following:

1. Numerical Value
00 Serial Interface K1
08 Serial Interface K1 and K2 (M.Y. 1997)
32 Auxiliary fan not available as of (M.Y. 1997)

2. Numerical Value
00 Engine version over CAN from instrument cluster (as of M.Y. 1997)
+08 Blower motor bar graph switched on by AUTO
+16 Refridgerant fill level check switched off
+128 SMOG display switched off

Should I be able to scroll through and see ALL of these values in their appropriate areas or is there only one choice per "numerical P-1 value" and the other 2 values are not applicable????

I'm a bit confused!

Thanks guy!

Matt L · #9 06-18-2006, 11:35 AM

There are only two values. Numerical value 1 is displayed in the right side when the left says P1. Similarly for numerical value 2.

You probably want 16 for P2. For P1, it seems that you'd want either 8 or 40 (8+32). What I posted there is all the climate-control diagnostic manual seems to say about these values. As I have a '96, I haven't investigated.

You already know this, but for others who may find this thread, you really should write down these numbers before you do anything like change them or change the pushbutton control module.

Bigdaddybenz · #10 06-18-2006, 10:03 PM

Hi Matt!

When I accessed the "P-1/P-2" values they were indicated as follows:

P-1 = 127
P-2 = 152

As per your advice I reset the P-1 value to: 40 and the P-2 value to 16.

As a result, I recovered my "horozontal arrow" option on the vent display area.

STILL, my left vents were putting out semi-cool air while my right vent was putting out ice cold air while both sides were in the AUTO/Lo mode.

I recorded the following values while using the test procedures from Steve's article:

1 = 30
2 = 45
3 = 25
4 = 22
5 = 23
6 = 93
7 = 12
8 = 53
9 = 04
10 = 6.0
11 = 2.5
12 = 4.2
20 = 2.0
21 = 07
22 = 00
23 = 00
24 = 13.1
40 = 71
41 = 36
42 = 40 <------ This number reflects the P-1 value as it changed accordingly.

Here's a real twister: The ONLY fault code that I have is ( I don't remember the exact nomenclature) as per the chart: "Non-American Fault"

I believe that I am STILL low on freon but the fluctuating reading that I get on #7 (which has been consistently 12-14bar, but has been as low as 9 bar) concern me.....

If I were to go the old fashioned route and dropped a gauge on the low side of the AC system, what type of pressure should I be looking for????

Once again, thanks BIGTIME!!!!

Matt L · #11 06-19-2006, 11:10 AM

The pressures depend on the temperature and the humidity inside the car. While you do have a high-side gauge built-in, it's better to just connect both of them so you can see what's going on. You'll need an assistant to keep the engine at 1500RPM.

#7 at 14 isn't very high, if it's hot. 9 is fine too, if it's cooling properly. But you may be low.

I see #10 is at 6.0 there. Your auxiliary fan was running, right?