My AC quit blowing cold suddenly in my 98 C280. I checked and the AC compressor is not coming on. I checked for codes on the climate control and found 230 and 235. I deleted them but code 230 immediately returns. Checked the sensor values and found 05 to read CL O. I have searched the forums and cannot find what CL O means. Any help would be appreciated.

 

I found this link to self diagnostics of Mercedes AC and Heating systems for 1990 - 1996. The procedures for climate control button sequence may be different but the codes are pretty much the same. It answered my question and I hope it helps someone else. Cheers

http://www.europeantransmissions.com...iagnostics.pdf

 

So did you replace the sensor? They tend to go bad fairly often, arent that expensive and can be done without too much hassle by dropping the panel underneath the dash and swapping it out.

 

Not yet, waiting for the shipment from auutohaus. Free shipping for orders over $50 so I ordered filters for for a 120k service too. The sensor at the dealer is $140 here in the Atlanta area, and less than $40 if you can wait a few days for shipping. Fortunately it isn't hot yet!

Once I replace the evap temp sensor and clear the DTC, will the compressor cycle long enough to take some freon? My pressure value is 4.0. I know that there is a slow leak in the system because I added a can of freon last spring.

 

We refilled mine last year, may need some more this year but it held up all summer long. I would think you could put the gauges on it and top it off without a problem. Dealer is ludicrous on their pricing, thankfully there are lots of places on the internet to shop.

 

Evap Temp Sensor R/R DONE.

Removed panel in footwell, located old sensor in evap housing. Unplugged the two wire connector and removed old sensor by lifting up on the exposed part like turning on a light switch. Had to turn it some to get it out. Easy.

Then I noticed it was a little different than the new one. It figures...

I took ohm readings set at 20k and got .17 on the old and 2.66 on the new. I compared the connector side of the sensors and found that the locking part (sensor to housing) was the same. Stuck it in the hole and it snapped locked. Hooked up the 2 wire connector and put the panel back. Took about 20 minutes.

Checked the climate control sensor values and it read 05 - 65. Started the car and checked freon pressures and put in about half a can of freon. BLOWING ABOUT 30 DEGREES. I'll check it in a couple of days to see if there was a leak as there are no signs of a leak now.

Thanks to this forum I saved some $$$$$ in helping in the diagnostics of the AC system!

 

The sensor was replaced in past. The new one should resist condensing water better than the old one.
You can not check the freon quantity by pressure. The system pressure depends on the temperature.