How To.. Perform An A/C Diagnostic Test R33

[Squeak]

Enter the diagnostic mode by pressing the OFF button for five seconds within ten seconds of turning the ignition on.
Sensor check
Sensor check is selected by pressing HOT switch (the red triangle) while in diagnostic mode. The microcomputer detects whether each sensor input signal is within correct parameters. The results are displayed on the screen.
If normal, a "20" is displayed.
If abnormal the failed sensor number is displayed. The sensor numbers are as follows:
20 - all is normal
21 - outside air sensor
22 - Inside air sensor
23 - Water temperature sensor
24 - Intake temperature sensor
25 - Sunload sensor (small sensor on the left hand side of the dashboard near the windscreen)
26 - PBR
27 - Refrigerant temperature sensor
This should tell you if any of your sensors are faulty.
Mode door position check
(This is probably not the cause of your problems but it is a nifty self check to play with).
While in Sensor check, depress the HOT button again. This will operate the the mode door actuator, and checks the whether the position detection switch is operating. Again the results are displayed on the display.
If normal, a "30" is displayed.
If abnormal the number of the faulty mode is displayed as follows:
30: Normal
31: VENT
32: B/L (Bi level)
34: FOOT
35: DEFROST/FOOT
36: DEFROST