bg1973

I've been reading the stickies and can't seem to narrow down my issue with AC. I have a 2000 E430. AC only works when the fan control is on high or almost high. It cannot be moved down more than two bars or the AC will start blowing hot. Most of the time, during short drives around town the AC always works as long as the fan is cranked on high and temperature at "LO" setting. When going on longer trips on the freeway, it works great until slowing down in traffic and blows hot again. Also if temperature is adjusted any higher than "LO" it will blow hot also. Clicking the EC button off, then back on always "jump starts the AC and it blows cold again until the next time it blows hot due to aforementioned conditions. The AUX fan seems to work at it should but there are times it is not running like when first starting the car. I did the double auto test to force the AUX fan and it runs full blast. I tried the "Easter egg" reset but it won't flash the lights back and forth on the buttons so that does nothing. I cleaned the contact for the AUX fan cable and issue persists. I cleaned the cabin temperature sensor and it appears to be functional, although seems to read a little higher that expected. Like 85 degrees when its more like 70 degrees in the cabin. The compressor pulley/clutch is always running as it should when the AC is turned on although still can blow hot.

Other things I did: disassembled, cleaned duo valve unit, new radiator installed, new water pump, new thermostat, new coolant sensor, recharged Freon. Freon seems to not allow me to add anymore and according to Freon gauge it should have slightly more in the system based on the outside temperature.

The values below in the first column are ignition on but not running the car. The second set of values are when running the car and AC is blowing cold.

Values don't seem crazy to me although 21 is odd as I get 2 values that change back and forth. For example, 32...255...32....255

If there is no value in the second column below it means there was no change between AC running or not.

Thanks for any input you guys can offer.


1. 125. 100
2. 100. 114
3. 76. 58
4. 76. 58
5. 76. 53
6. 148. 175
7. 07. 14
8. 94. 127
9. 27. 37
10. 0.8 6.0
11. 3.0.
12. 4.1
20. 3.2. 7.8
21. 32 / 255. 42/255 (Values toggle back and forth)
22. 00
23. 32
24. 11.4. 13.3
40. 164
41. 91
42. 00
43. 00

Plutoe

do and post the fault and actual value tests!

bg1973

Sorry, forgot to include: No AC fault codes in AC diagnostic mode. Also no scanner OBDII codes either. In addition, the radiator fan clutch was just replaced and coolant hovers around 80C most of the time. This did nothing to help.

Plutoe

You have been misinformed---use the AC controller to do the fault and actual value tests---see the stickies thousands of folks before you have done the test!

bg1973

Yes, as I mentioned I used the AC control unit to enter climate diagnostic mode. This is the mode with the "EB1" codes, etc. No error codes found. I will get a set of gauges today to get more information on the system status. I am suspecting the expansion valve at this point or the AUX fan control module.

Plutoe

Grab a hammer and hit yourself beside the head---the test you are running is the fault test and not the actual value test--you will save yourself loads of time if you try to understand the cars AC system!

bg1973

This values (from my first post) are not what you are referring to? 1. is cabin temperature, 2. is outside temperature, etc. First column, system off key in position 2. Second column, values while car is on and AC is blowing cold. If no second value listed, no change of value occurred when AC is on or off. 21. speed sensor gives two values blinking back and forth. This seems odd as no other posts I read in stickies has dual values flashing for speed sensor 21. Other values seem to be within the normal operational temps although cabin sensor seems a bit high.

1. 125. 100
2. 100. 114
3. 76. 58
4. 76. 58
5. 76. 53
6. 148. 175
7. 07. 14
8. 94. 127
9. 27. 37
10. 0.8 6.0
11. 3.0.
12. 4.1
20. 3.2. 7.8
21. 32 / 255. 42/255 (These values toggle back and forth)
22. 00
23. 32
24. 11.4. 13.3
40. 164
41. 91
42. 00
43. 00

kajtek1

Instead of chatting with clown, you can go to proper help site.
Read whole page and post full troubleshooting numbers here.
Partial data will give you partial diagnosis, or clowning around.
http://www.mercedesmedic.com/ac-air-...le-codes-list/

Plutoe

Watch out for bonehead spammers--------


The concerns are 7(refrig pressure) first value 7, second value 14---the 7is bad the 14 is good. number 5(evap temp), both values of 76 and 53 are bad should be 41.


You either have a faulty compressor or you are low on refrig.