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1997 S500
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Discussion Starter #1
Climate Control Unit Specifics

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Having trouble with my AC and need to check what the proper version coding, the P1 and P2 values, should be on my push button unit. I have gotten info like this:

P1
C00 - new,not programmed
00 - Model 140 (as of MY 1997)
01 - Faren. degrees displayed (up to MY 97)
03 - Cel. degrees displayed (up to MY 97)
72 - Serial interface K1 and K2 programmed (as of MY 97)

P2 Engine version
01 - M 104 (up to MY97)
02 - M 119 (up to MY97)
03 - M 120 (up to MY97)
04 - OM 603 (up to MY97)

+8 to engine version --- blower motor speed on in AUTO mode
+ 128 to engine version ---- SMOG display readout switched off


My unit P/N is 140 830 2385. My P1 was set at 75??? My P2 was 125??? Am I being dumb? I believe my settings should be P1 72 and P2 130. Can any one shed some light on this? What are the common pairings of P1 and P2? I have seen common set ups for the 210 push button unit, but not for the 140.

One other note; I am continually getting an error code B1426 on the control unit and cannot find this trouble code listed in any form. Has anyone seen this?

Thanks for your time.
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1997 S500
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59 Posts
Discussion Starter #3
Sorry about so many posts...new to the game. The car is as the post says W140 S500 1997 M119 engine, left engine spec out before. I did try to set P1 to 72 today, but when I did, the push button unit automatically switched it to 08????? Looked at your thread and it didn't help me. Do you have access to the Startek info?
 

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1998 140.070 CL500, 1966 406.121 U65
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1,463 Posts
Sorry about so many posts...new to the game. The car is as the post says W140 S500 1997 M119 engine, left engine spec out before. I did try to set P1 to 72 today, but when I did, the push button unit automatically switched it to 08????? Looked at your thread and it didn't help me. Do you have access to the Startek info?
Are you sure that its not P2 that is set to 8?
Since, for MY 1997, P1 is set to 72, it will get engine size from KI, and then
all left for P2 bits to signal, is the;

+8 to engine version --- blower motor speed on in AUTO mode
+ 128 to engine version ---- SMOG display readout switched off

I must say I'm not completely sure, but compare to this old thread also;
http://www.benzworld.org/forums/w140-s-class/1442153-w140-plug-n-play-i-think.html#post3462815

br,
syljua
 

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1997 S500
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Discussion Starter #5
First, I want to thank you for your help. It has been fairly frustrating. I tried storing 72 in P1 three separate times and it constantly and immediately kicked it back down to 08. More and more I am thinking the unit is my problem. I've had the system checked for leaks, had vacuum tests done and it all checks out OK(by 2 independent shops). I have finally found what my recurring DTC b1426 is, and it indicates the rear coolant circulation pump is faulty. (should have nothing to do with AC) I've looked at your old thread and I have all the programming info. I really think the values should be P1 72 and P2 136, it just won't take the 72. Funny thing is that after I had leak tests and reset, the system would work fine for about 5 to 7 days and slowly degrade to blowing regular air. Any other ideas? Hate to take it to someone without me really nailing down the issue a little more or just jumping into getting another control unit.
 

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1998 140.070 CL500, 1966 406.121 U65
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I have finally found what my recurring DTC b1426 is, and it indicates the rear coolant circulation pump is faulty. (should have nothing to do with AC)
Well, considering that the control panel controls both heating curcuit and cooling AC part,
a DTC regarding heat belongs here (but, yes, not perhaps related to you problem).

The motor and duo-valves for the rear AC are in the passenger footwell (under the side
skirt on right hand side, aft of the front wheel).
Given that you actually have rear AC in your car, right?

The refrigiator lines of the rear AC is located in the corresponding left side of the car.
(under the left side skrit aft of wheel).

Perhaps you should have a look at those, to see it there are any obvious problems
with rust, etc.?

br,
syljua
 

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1997 S500
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Discussion Starter #7
Thanks...I'll check it out..I tried inputting the 72 on P1 again (in case I wasn't holding my tongue right) on the push button unit and it kicked it down to 08 again. It will let me put in 73 and almost anything else, but not 72....not funny.
 

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1998 140.070 CL500, 1966 406.121 U65
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Thanks...I'll check it out..I tried inputting the 72 on P1 again (in case I wasn't holding my tongue right) on the push button unit and it kicked it down to 08 again. It will let me put in 73 and almost anything else, but not 72....not funny.
Yes, I checked mine this morning. It was at 75 (from KI and Celsius), but
setting it to 72 behaves like you're saying. Even made a video of it...;


So, set it to 73, and you should be fine at least with respect to version coding.

Guess; if the rear coolant (heater) motor does not transport to rear, would'nt it build
up warmer and warmer water for the rest of the system, giving warmed air?
Could you do a readout of the AC diag values when system is functioning ok, and another
when not, and list them here?

br,
syljua
 

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1997 S500
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Discussion Starter #9
Great video! My unit seems to be behaving properly. P1 is 75?...strange..that was what mine was originally also, but tell me how do you get that number from all of the set up data that you read? Do you mind telling me your P2? I believe mine was something like 125, but since I did not write it down and have messed with it so much, I am not sure. I am thinking safe with 136, but looking at chart +8 and +128 should be added to my (M119) 02 value...meaning 138?

Other good news (or bad) is that a friend and I were double checking the mechanics and found dye near the front left wheel well. There is a rusty line there that I believe goes to my rear AC and it must have a leak. Makes it kind of hard to trust any garage/repair place even though they come highly recommended when they say there are no leaks in the system.

I think I am seeing the light at the end of the tunnel, but I still haven't tackled the rear water pump issue...probably rust also (same area just the other side of car)
 

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1998 140.070 CL500, 1966 406.121 U65
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1,463 Posts
Great video! My unit seems to be behaving properly. P1 is 75?...strange..that was what mine was originally also, but tell me how do you get that number from all of the set up data that you read? Do you mind telling me your P2? I believe mine was something like 125, but since I did not write it down and have messed with it so much, I am not sure. I am thinking safe with 136, but looking at chart +8 and +128 should be added to my (M119) 02 value...meaning 138?
My P2 is a 8. I'm still confused about the P1, but P2 behaves like expected I think.
If you see the numbers displayed, its 8 and 128, bit number 4 and 8 in a 8 bit byte.
I thought that P1 also would get the C or F from Instrument Cluster, but rgds P2
I'm pretty sure that it gets the engine type from IC.

So, possible P2 values for a 1997 will be;

00000000 : 0
00010000 : 8
00000001 : 128
00010001 : 136

Other good news (or bad) is that a friend and I were double checking the mechanics and found dye near the front left wheel well. There is a rusty line there that I believe goes to my rear AC and it must have a leak. Makes it kind of hard to trust any garage/repair place even though they come highly recommended when they say there are no leaks in the system.
Good that you at least have found some explanation to the problem:)

br,
syljua
 

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1996 s320
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i have 1996 s320 swb vin#WDBGA32E4TA312860
i accidently changed my p1 and p2 values and now i can't seem to get them back correct. also my red and blue hvac buttons no longer work. any help would be greatly appreciated.
 

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1997 S500
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Discussion Starter #12
I would have been able to answer you immediately a year ago, but this info has now been pushed from the brain. Let me check some of my notes that I have and I will get back to you, but I think you do need the red/blue buttons on either side to set the values. Not 100% sure though. Sounds like a bad unit if your temp control buttons won't work.
 

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1996 s320
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Any help would be appreciated. My buttons on controller work. I was talking about the buttons between the vents. They used to work before I messed with the settings.
 

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1998 140.070 CL500, 1966 406.121 U65
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i have 1996 s320 swb vin#WDBGA32E4TA312860
i accidently changed my p1 and p2 values and now i can't seem to get them back correct. also my red and blue hvac buttons no longer work. any help would be greatly appreciated.
Where in the procedure of changing p1 and/or p2 does it break down.
I think you'll have to elaborate a bit more.

br,
syljua
 

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1996 s320
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Everything was working except one of my temp up buttons so i tryed a 210 controller. it didn't work so i put my old controller back in. everything was working until i altered my p1 after that my ac blows weak and the buttons between the vents no longer functioned when pushed. my p2 value is set at 128 wich i think is correct but my p1 was at 176 before i realized that i shouldn't be altering it. I need to know the correct values so i can set it back to factory.
 

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1998 140.070 CL500, 1966 406.121 U65
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Hi,

The correct values for your car is dependent on you cars production month.
Apparently, theres differences in codes up until 05/1996 and 06/1996 on.

Have a look at this post;
http://www.benzworld.org/forums/w140-s-class/1442153-w140-plug-n-play-i-think.html#post3462815

So, if your car is up until 95/1996, I think the codes should be;

P1: 01 (if you want C in the display, P1 should be 02)
P2: 01 or 09 or 129 or 137 (dependent on which indicators you want to be shown)

Important here, is to tell it thru P1, Celsius or Fahrenheit, thru P2, that its a M104 engine.

Now for 06/1996 and newer.

P1: 00 (or 72, not sure here)
P2: 8 or 128 or 136 (again, dependent on showing of indicators in display)

So, for 06/1996, the unit will get the C or F setting, along with the engine version,
from other units in the car.

It seems like 176 for P1 is not a possible value for W140, so try to change that.

Hope it helps.

br,
syljua
 

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1997 S500
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Discussion Starter #17
Ok....just checked mine...my s500 date on door sill is 02/97

P1 is 75
P2 is 136

Has worked great ever since the leak was fixed. I never mess with the center buttons between the registers. Aren't they just there to force hot or cold air through the vents? I could be wrong, but I just leave my unit on auto. I think one time I had the AC on with the cold button on up top and somehow the side vents started blowing hot air. Ever since then, I've never touched those buttons. Maybe someone else can answer the real function of the buttons and when you actually need to use them.
 

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thanks for everyones help. its been snowing so haven't had a chance to check on it. But i do appreciate everyones feedback. hopefully i get a chance this weekend to play with it.
 

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Thnx everyone again finally got a chance to get outside and check my settings. My car was made in 02/96 i used p1 01 p2 129 and everything is functioning great. You guys have beeen extremely helpful.:):):)
 
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