98 C280 (W202) Won't cool
 

I have tried to find diagnostic codes specific to my 98 C280, but can only get close. Sometimes when I first crank the engine and turn on the AC, it will begin cooling, then a few minutes later the air goes hot and it will no longer cool. Since I do not know what all the codes are, I took the codes with the engine off, cranked it and then took down the codes about 10 minutes later. This is with the Auto ON and set to 72 degrees F.

01 82F 82F
02 75F 76F
03 83F 79F
05 150 149
06 118 129
07 06*3 06*1
08 82F 80F
09 33F 33F
10 250 260
20 00 00
21 000 000
22 000 000
23 000 000
24 11.7 13.9
40 02 02
41 03 03
42 18 18
43 6-C 6-C
50 80F 78F
51 72F 72F
52 50F 50F
54 OFF OFF

Any thoughts on what is wrong with my puppy?

Just out of curiosity, you don't have the center air vents pointed straight up at the area with the interior lights, do you? If so, that is where the interior temp sensor for the car takes its reading and if you do have the vents pointed that way then the car will think its cold inside and shut off the A/C.

What you posted are not codes, but simply live data. What were the circumstance in the car when this data was taken? Was the car standing still, moving, was the air coming out the vents cold?

#1 is interior temp sensor. At this point, looks like it should be working and commanding the car to cool down.
#7 is refrigerent pressure in bars. If the car was standing still with the A/C blasting, this number seems low.

I didn't know about the location of the sensor! Thanks! No, all the vents were pointed straight ahead.

The car was standing still and the air was NOT cold from the vents.

Judging from the refiregerent pressure, it seems like the A/C compressor may not be running. Did it engage? Another idea may be a faulty evaporator temp sensor that is not letting the compressor engage.

I'm thinking temp sensor. Mine failed and this was the symptom. It just would not blow cool.

Where is the temp sensor located?

They replaced a pressure sensor some time ago and after that it worked. The compressor is not engaging during this time.

Where is the evap. temp. sensor located?

The evaporator temp sensor is located on the evaporator. The evaporator is located in between the driver's and passenger footwells where the heater core is located. One of those numbers from the data is the evaporator temp sensor, but I forget which one. If no one else knows, i can look it up and get back to you. Essestially if the evap temp sensor is faulty, it will inhibit the compressor from engaging.

On my '96 C280, number 5 is the evaporator temp sensor. I think that yours is the same. A reading of 150 means it has gone south. I just replaced mine last weekend. It took about an hour. Nothing too difficult. I'll post the details if you want.
Dan

Fantastic, Dan! If you could just give me the basics, I would be forever in your debt!

A/C Evap Temp Sensor price?
 

This may be one for our guys at Fastlane, but when I checked for the A/C Evap Temp Sensor, it gave me R1071-86215 at a Retail Price of $35.00 and "Our Price" of $42.08!! Hmmmm, what's wrong with this picture? Guess I need to find out who sells them at "Retail Price"! :D

Keep in mind, this is for a '96 model year. Hope yours is the same. Buy a new sensor. Removethe plastic panel under the dash, driver's side. Look carefully for all the screws and remove them. The big white hold-down needs to be pulled/turned. It will pop off. The only sneaky one is up in a deep hole above the right knee/shin area. Just get up in there with the right size socket and remove it. Remove the screw at the hood release lever and work the release cable off the lever. With all the screws removed, the paned will slide back and release. Have the new sensor in hand so you can see what you are looking for. Get on your back and put your head under the dash as far as you can and you'll see the tail end of the sensor sticking out of the plastic evaporator housing right above your head. Just pop it out and install the new one. If your steering wheel adjusts back and forth like mine, be careful re-installing the locking lever. It is easy to get it in the wrong place. Check its action before your button everything up.
Good Luck, Dan

Did the replacement last night and it went smoothly. Your description was close enough that I was able to complete it with no problems. My number 05 NOW actually shows the evaporator temperature instead of "150"!

Thanks to all of you great guys for all your help and input. You never cease to amaze me!

Now, on to the NEXT problem.......... :confused: