Quote:
Originally Posted by Kaz26
I drove my car the other day for the first time in about 2 weeks and the AC wouldn't get cold. I drove for about 20 minutes and it was still blowing warm.
What I've checked:
I checked the fuses, they all looked good, then I checked the low side pressure refrigerant line with the car running, AC on full blast set to the coldest temp (60F degrees) and it seems rather high at 85psi. I haven't checked the high side yet. Ambient air temp was about 80 degrees when I checked the low pressure side.
When I looked at the compressor with the car running, the center part just spins constantly whether the AC is running or not. So it seems like the problem is related to the compressor in some way. I will post INPA screenshots below. I'm not sure what to look for in it, but maybe someone here will.
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Your compressor is NOT operating. The key is in the SECOND screen you attached, which is actually the FIRST screen
in F1 AnalogPorts when you select that from the F5 Status Screen after connecting to the IHKA Module.
A correct translation of the German technical terminology used in INPA is found in the attached INPA IHKA Tutorial pdf.
I have attached a copy of that screen translated properly to English, with some additional Notes on the significance of the data.
1) The bar graph in the Lower-Left of that screen is HIGH SIDE Refrigerant (R-134a) Pressure in bar units, 1 bar - 14.5 PSI.
7 bar = 7 x 14.5 = 101.5 PSI & 101.5 PSI - 14.5 = 87 PSIG; The original German was "Druck Kaltemittel" =
Refrigerant Pressure
2) The Evaporator Temperature (temp of the A/C cooling coil in dash) is shown in the 2nd bar graph from bottom on Right, degrees C
Refrigerant pressure of 6 or 7 Bar is certainly sufficient to engage Compressor Valve, so your issue is NOT low refrigerant.
Your Evaporator Temp (per sensor contacting Evaporator/ Cooling coil) is 44C which is 15C HIGHER than Outside Temp -- NO Compressor.
If you have manifold gauges connected to BOTH High Side and Low Side, BEFORE starting engine, after sitting overnight,
you would find the High Side & Low Side pressures equal, the system having attained equilibrium after ~ 5 hours static condition.
Measure the High Side & Low Side pressure any way available to you. That IHKA screen from INPA shows HIGH SIDE,
so if you have a charging handle/ Can Tap with gauge to measure Low Side, you can read BOTH. NOW, start engine and
with "Snowflake" LED on R side of A/C control panel lit and A/C MAX button pressed, see if either High or Low side readings change.
If they do NOT, then you have NO compressor operation. Check back with test results and someone can suggest "next steps."
COMPRESSOR VALVE:
The Denso Compressor used on (Most?) E9x models does NOT have a clutch
but rather uses a "Compressor Valve" to control whether
the compressor pumps R-134a or NOT. The Compressor Valve (Y2b) is connected to and controlled via the JBE Module.
The front of the Compressor ALWAYS looks the same, whether the compressor is pumping or NOT. You will see NOTHING
different as far as what is turning externally whether pumping or not. There is NO clutch plate to "click in" or turn when engaged.
Here are some links for more information about the Compressor & System:
https://www.newtis.info/tisv2/a/en/e...eos/1VnY9cKgnR
https://www.newtis.info/tisv2/a/en/e...ioning/25K67rA
Here is the TIS circuit diagram for Climate Control Functions on your 2008 335i E90:
https://www.newtis.info/tisv2/a/en/e...bution/uZS1ONq
NOTE: the Refrigerant Pressure Sensor (B8) and Compressor Valve (Y2b) are BOTH connected to the JBE, and you
can also read information and Fault Codes (F4 Fault Memory/ Fehlerspeicher) by connecting to the JBE Module.
I'm NOT aware of any way to Activate or Control the Compressor Valve for test purposes, either when connected to IHKA or JBBF/JBE.
ANYONE knowing of any way to Activate or monitor actual Control Valve position please advise.
George