yesterday on a trip to Phoenix, my AC started to blow only moderately cool air. Figuring it was probably low on cold juice, I picked up a can of 134a and added it in the parking lot without checking pressures. This cooled things down a bit, but it still doesn't seem cold enough.

The ambient temp is around 107-110*F.

So today I pulled the sensor readings and codes from the climate control.

1 - 92
2 - 127
3 - 69
4 - 70
5 - 64
6 - 207
7 - 16
8 - 127
9 - 9
10 - 3.4
20 - 5.5
21 - 14
22 - 0
23 - 0
24 - 14.2
40 - 8
41 - 5
42 - 248
43 - 14

Eb1232 - - Refrigerant Pressure Sensor Malfunction
Eb1416 - - Coolant Circulation Pump Malfunction
EFF

so I think the barometric pressure of the freon is a tad high which probably means I overcharged it some. The bumper temp sensor doesn't seem right to me since ambient is 107 (unless this is the condenser coil temp???)

The compressor does run obviously, but I'm really at a loss as to what the issue could be. Even at 107 ambient I should pull colder than mid 60 degree evap temps i'd think.

Can anyone shed some light for me. Is the 127* on the bumper temp an issue? I was thinking possibly a bad expansion valve, but it's really just a wild guess.

-J

 

I want to add here that it's possible the pressure sensor switch malfunction could be because I had the connector disconnected earlier this morning. Is there a way to reset the codes?

 

The problem seems to be the Freon pressure sensor. I've never changed one, but aren't those about $40 at Autohaus AZ? It screws into the receiver dryer.

 

To clear the code you need to get back into the diag mode and when on the offending code press and hold both AUTO buttons for at least 2 seconds. You should see a dd showing that its deleted. The B1416 came up on my car when the freon level was a little low but only 1/4lb off. Its been evac'd and refilled - hasn't come back but I suspect it has to do with my battery which was generating a ton of low voltage errors - as reported by the Star system.

I don't want to sound pedantic but a proper AC charge - evacuating under vacuum and a fill by weight factoring in temp and humidity is really the only way to preserve an AC system as well as to keep it working properly. Overcharging or undercharging with moisture in the system will destroy it.

Your #6 is more than likely defective. The only way to change it is to evac the system. Its not a Schrader valve sensor which can be removed and reinstalled without removing the gas from the system.

For about 100 a good ac shop can do the evac and fill - replace the sensor (id replace both at the same time and have the 0 rings changed) or even replace the drier if the system had been opened in the past. Gas it up and have the pressures checked.

You should get about 38-40 at the evaporator sensor even with the heat reported - even at idle. In St Louis my 2000 CLK430 will get those values sitting in the sun with ambient about 102 or higher. It takes only a few minutes for the drop and it will maintain the 38 (even 37) at speeds of 4-5 on the display.

 

I ordered a high pressure hose from the drier to the expansion valve, an expansion valve, a drier, and a pressure switch. Since these things need to be replaced anyhow even if the compressor is dead. I will hope that my problem is a clogged/faulty expansion valve and if needed I can replace the compressor as a last resort. From what I gather all readings on the climate diag seem basically correct(not bogus). The freon pressure was high since I overfilled the system hence reading 16 bar at idle. (my low pressure guage was reading 75lbs with system running) Also, #6 is coolant temp so 207 is not out of the ordinary here either. The car was being driven on the highway at 110* ambient, then stopped and idled for 3 min while taking these readings. So 207*f is right on the money. I'm really thinking this is an expansion valve issue. The compressor is working, and the compressors i've actually seen fail have not failed halfway. They usually stop working altogether either by seizing or not pumping at all.

I do have a vacuum pump to pull a good vacuum in the system for a couple hours, a scale to measure freon added, and a low pressure guage. My only missing tool is a high pressure guage, and if I need one the harbor freight is only a couple miles away.

So at this point I am about $120 in the hole minus the 134a (which i'm not sure I'm going to use) I may go with one of these new propane/butane based blends instead... less refrigerant, less head pressure at the compressor. This is yet to be decided since I'm wondering how critical temps and pressures are to this system with all of the electronic control. May be best to stick with 134a or a blend say of 50/50.

 

re:compressor not running..
with advice from Marcus...after I cleared my codes... the compressor ran fine.