98 E300 turbo a/c trouble - PeachParts Mercedes-Benz Forum

mdisav · #1 09-08-2007, 08:05 PM

It is blowing warm and the compressor is not kicking on. I did the diagnostic from reading prior threads and I got:
b1227 outside temp sensor
b1230 evap temp sensor
b1231 ect sensor
b1234 sun sensor
b1235 emissions sensor
b1419 electromagnetic clutch
b1459 series interface connection to instrum. cluster.

With all the talk of the evaporator temp sensor being the culprit a lot of the time I decided to replace it.
Still no compressor kicking on.
Is there a way to clear the codes?
Anyone know what to do next?

okc329 · #2 09-08-2007, 09:17 PM

I wonder if you have a fuse out.

mdisav · #3 09-08-2007, 09:38 PM

Hmm. I did not even think of that. I will check.
Thanks!

sokoloff · #4 09-08-2007, 11:03 PM

Is your Economy light always on?

mdisav · #5 09-09-2007, 07:55 AM

No, the ec light is not on and it has a full charge.

Matt L · #6 09-09-2007, 09:33 AM

Record the current sensor values. That will tell if the evaporator sensor is bad.

mdisav · #7 09-09-2007, 10:18 AM

I forgot about doing that test and I will not be with the car until tomorrow. I will do that and report back.

mdisav · #8 09-10-2007, 07:12 PM

All values were correct. Put 12volts to the compressor and nothing. I will be replacing it and I believe all is well.

Thanks for you posts!

RRags · #9 09-22-2007, 06:46 PM

Quote:

Originally Posted by mdisav

All values were correct. Put 12volts to the compressor and nothing. I will be replacing it and I believe all is well.

Thanks for you posts!

I know my right side duovalve is malfunctioning (not stuck, electrical as I noticed a burn score on top of wire spool -- valves free). The diagnostics also backed me up on that right side and an MB indie said most often it is the electrical component of duovalve which goes bad). Anyway, drove home Thurs nite with a/c and no a/c all day Friday. Foolishly sent home two cans of arctic freeze and still nothing. Checked all values on diagnostics and got the following:

Friday Saturday
1 -- 89 84
2 -- 94 80
3 -- 121 89
4 -- 145 105
5 -- 143 134
6 -- 182 120
7 -- 28 but decreased to 24 12
8 -- 121 but increased to 123 84

The trouble codes were: 1418 1425 1235
Would only blow hot air (all vents not just passenger side which I'll keep closed until I replace duovalve). Also, auxiliary fans came on immediately upon cold start -- figured some sensor problem. Same thing this morning (Sat -- the above readings were taken Sat afternoon). Let out freon and some oil came with it as now gauge was reading in the red; no wonder compressor wouldn't engage) Saw code 7 at 17 and went up to 21 as I drove and accelerated, meaning better pressure. What happened Friday? I mean I am glad a/c is working now and I know I need to replace the duovalve but what the hell gives? Also, have read about the evaporator temp sensor but I'm still not sure where it is or how to access same without creating problems. Could this be my intermittent problem? Or is the right side of the duovalve causing the problems. I'm in Florida and must have a/c. What a system which one older guy told me was modeled after the Rolls Royce system. A veritable rube goldberg of a system. I replaced my Yukon's entire system (shop did evac and recharge for 90bucks) for 435 only because condensor fitting was galled so it would have been 170 less. Anyone please care to comment and perhaps steer me in right direction. It's a 99 E300 turbo. Thanks, Rick

Matt L · #10 09-22-2007, 07:44 PM

Mechanically, the system is the same as in earlier models. Electrically, it is quite different.

You can eliminate the effects of the duovalve by clamping the outlet hose. Then see what you get. These are showing higher than ambient, so you would seem to have some coolant flow through the heater core.

Clearly there was too much refrigerant when you got the 28 reading. That will trigger the auxiliary fan at high speed.