Preparation for Test 1. Set temperature selector wheels to white area. 2. Ignition: ON 3. Press left and right button. 4. Wait at least 20 seconds then press for more than 5 seconds. 5. The number will appear in the left display window, in the right window the momentary in-car temperature will appear, or, if there is a short circuit, if there is an open circuit. 6. By pressing the left button the next value will be displayed in the right window (see table on following page). 7. Press button to end test program.

Display code in left window	Possible cause	Remedy/Test Step 1)
	In-car temperature sensor with aspirator blower (B10/4)	23 4.0
	Outside temperature sensor (B10/5)	23 5.0
	Left heater core temperature sensor (B10/2) 2)	23 7.0
	Right heater core temperature sensor (B10/3) 2)	23 8.0
	Evaporator temperature sensor (B10/6)	23 6.0
	ECT sensor (A/C) (B10/8) 2)	23 9.0
	Refrigerant pressure in bar ( = 6 bar)	23 10.0
	Blower control voltage from (MIN) - (MAX)	23 13.0
	Software status, A/C pushbutton control module (N22), manufacturer Bosch: , etc., manufacturer Kammerer: , etc.	-
	Left rear heater core temperature sensor (B10/9)	23 34.0
	Right rear heater core temperature sensor (B10/10)	23 35.0
	Rear evaporator temperature sensor (B10/11)	23 33.0
	Software status, rear A/C pushbutton control module (N22/3), manufacturer Bosch: 42 3)	-
	Control module applicable for active charcoal filter = yes, = no.	23 17.0 , 18.0

1) Observe Preparation for Test, see 22 . 2) Display will read only two digits (example: temperature of will read ). 3) Starting 02/92.