Select Monitor Adapter
Subaru Diagnostic Ports
How to build a PC adapter

Engine Control Unit (ECU)
Reading Error Codes
Reverse Engineering
ROM images

Transmission Control Unit (TCU)
Reading Error Codes
Reverse Engineering
Power Mode
ROM images

Other Control Units
Air Conditioning Unit
4WS Control Unit
Cruise Control Unit

OBD2 Information
Select Monitor Cartridge

Links to other sites

Custom TCU Development

Zexel Air Conditioning Control Unit

We haven't investigated the diagnostic features of the Air Conditioning Control Unit in much detail. The data returned by querying it suggests that it is a much simpler device than the ECU and TCU. There appear to be only 32 addressable locations.

Here are the values returned by querying each address.

00000000   00 9D 8F 98 00 00 40 AF B5 70 6B 0E 6E 00 00 00
00000010   00 59 00 02 00 81 00 00 00 00 00 00 00 00 00 00

The control panel is slightly different on a USDM SVX. See picture below. The buttons are as follows: 01=Recirc, 02=Demist, 03=High, 04=Med, 05=Lo, 06=Econ, 09=Auto, 0A=Off, 0B=Out_Temp, 0C=Vent

The locations in the table below were extracted from the Select Monitor Cartridge.
000B" Tset (F01) "Temperature Set on Panel(x*0.5) + 18 deg
000C" To (F02) "
0001" Troom (F03) "Room Temperturex*0.5 - 50 deg
0002" Tamb (F04) "Ambient Temperturex*0.5 - 50 deg
0003" Tevp (F05) "Refrigerant Temperaturex*0.5 - 50 deg
0004" Qsun (F06) "Sun Load Factor
0004" Tsun (F07) "Sun Load Temperaturex*0.5 - 50 deg
0005" Tref (F08) "Coolant Temperaturex*0.5 - 50 deg
0006" Tw (F09) "Wind Temperaturex*0.5 - 50 deg
0007" AMRset (F10) "AMR Target(Active Magnetic Regenerative)(%)x*100/255
0008" AMRpot (F11) "AMR Actual(Active Magnetic Regenerative)(%)x*100/255
0009" MODEset (F12) "Air Outlet (Target) (%)x*100/255
000A" MODEpot (F13) "Air Outlet (Actual) (%)x*100/255
000D" BLW (F14) "Blower Voltage (V)x*0.04
000E" Intak (F15) "Air Inlet0:Circulation / 2:Fresh Air
0010" Isol (F16) "Solenoid Current (A)x*0.005
0011" EGItoA/C(F17) "A/C Compressor (%)x*100/255
000F" Sw (FA0) ""0", "CIR", "DEF", "FAN", "4", "5", "A/C", "+", "-", "AUTO", "OFF", "OUT TEMP", "MODE"
0012" DIAG.COD(FB0) "

Thanks for Noriyasu Mori for assistance with collecting this information