Auto+Climate+Control+Diagnostics

toc If your climate control is giving you issues, the control unit has a self-diagnostics feature, similar to the ECU.

//Original writeup from TTZD.com.//

=Procedure=

Entering Diagnostics Mode

 * 1) With the ignition switch turned ON, Press AUTO and OFF simultaneously for 5 seconds (step 2 in above image.). This will activate the Monitor Diagnosis Mode (step 3 in 1.)
 * 2) Pressing AUTO again will switch to the Actuator Test Mode (step 4 in above image.).
 * 3) Pressing AUTO again will switch to the Upper and Lower Temperature Difference Adjustment Mode (step 5 in above image.).
 * 4) Pressing AUTO again will switch to a readout of Trouble Codes (step 6 in above image.).
 * 5) Pressing AUTO again loops back to Monitor Diagnosis Mode (step 3 in above image.).

Monitoring Diagnostics Mode
The control unit will display temperature data in this mode. The step monitor will have the right single dash lit (step 3 in above image.). Temperature data is returned in the display's 'Set' digits.

Use the Mode switch and the Fan switch to toggle through the menu items.
 * ~ Def icon only ||~ Ambient temperature ||~ ºC(ºF) ||
 * Upper vent icon only || Upper cabin temperature || ºC(ºF) ||
 * Lower vent icon only || Lower cabin temperature || ºC(ºF) ||
 * 0 Fan & Def icon || DEFROST outlet air temperature || ºC(ºF) ||
 * 0 Fan & Upper vent icon || VENT outlet air temperature || ºC(ºF) ||
 * 0 Fan & Lower vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">FOOT outlet air temperature || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ºC(ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/4 Fan & Def icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Sunload || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">*1 ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/4 Fan & Upper vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">water temperature *3 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ºC(ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/4 Fan & Lower vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Mode door voltage *4 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">*2 ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/2 Fan & Def icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">N/A ||  ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/2 Fan & Upper vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">N/A ||  ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/2 Fan & Lower vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">N/A ||  ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">3/4 Fan & Def icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">N/A ||  ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">3/4 Fan & Upper vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">N/A ||  ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">3/4 Fan & Lower vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">N/A ||  ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Full fan & Upper vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Difference in upper & lower temperatures || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ºC(ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Full fan & Lower vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">N/A ||  ||
 * 1: One tenth of the value in kcal/h*m² unit
 * 2: Ten times the value in V
 * 3: When coolant temp. is below 40ºC(104ºF), indicates 20ºC (68ºF). When coolant temp. is above 40ºC(104ºF), indicates 80ºC (176ºF)
 * 4 Mode door voltage: 0 = VENT, 5 = DEFROST

Actuator Test Mode
<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">The climate controller will force actuators to work in this mode. The step monitor should be the right two dashes lit (step 4 in **1.**). The 'Set' digits in the display are the Mode door voltage, 0 = VENT, 5 = DEFROST. I'm not really sure what mine means with a 49 listed. Mode and fan speed can be set independently. When the upper and lower vent icon appears, a stabilized outlet temperature 30ºC(86ºF) is reached after the air mix door has be working for about a minute. <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Use the Mode switch to toggle through the menu items.

||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Defrost icon ||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Defrost and lower vent icon ||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Upper and lower vent icon ||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Upper vent icon || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">operating condition of the actuators cannot be checked by indicators alone. <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Use the Fan switch to toggle through the menu items.
 * = <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Mode door ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">DEF ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">DEF/Lower ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">B/L ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">VENT ||
 * = <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Intake door ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">FRE ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">FRE ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">50% FRE ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">REC ||
 * = <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Air mix door ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Full hot ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Full hot ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">30ºC(86ºF) ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Full cold ||
 * = <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Compressor ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">OFF ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">OFF ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ON ||= <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ON ||


 * ~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 12px;">Blower Motor ||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/4 Fan ||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1/2 Fan ||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">3/4 Fan ||~ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Full fan ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Voltage || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">4V || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">6V || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">9V || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">12V ||

Upper & Lower Temperature Difference Mode
Adjustments can be made to the difference in upper and lower target temperatures in this mode. The step monitor should be 3 dashes (step 5 in 1.). The 'Set' digits in the display will show how much of a difference by 'data' numbers in relation to temperature difference.

Using the Fan and Mode switches to raise or lower the data number: The programmed differences are stored until changed again, or the battery is disconnected.
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ºC spec. || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Data || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-20 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-1 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">0 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">1 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">20 ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ºC spec. || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Difference between upper and lower target temperatures || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-2.0ºC || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-0.1ºC || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">0 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">0.1ºC || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">2.0ºC ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ºF spec. || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Data || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-36 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-2 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">0 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">2 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">36 ||
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">ºF spec. || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Difference between upper and lower target temperatures || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-3.6ºF || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">-0.2ºF || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">0 || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">0.2ºF || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">to || <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">3.6ºF ||

Trouble Codes
The auto climate control stores error codes for later retrieval. The step monitor should be 2 dashes with a space in-between (step 6 in 1.). The 'Set' digits will show the number of ignition ON/OFF cycles since the problem was last detected. A dash '-' in the step monitor to the far left indicates a short circuit. A '|' hash in the step monitor on the left indicates an open circuit.

Use the Fan and Mode switches to raise or lower the code to change the desired data or status reading returned. <span style="font-family: Arial,Helvetica,sans-serif;">[0.1657kW (142.51 kcal/h, 565.5 BTU/h)/sq ft.] ||
 * ~ <span style="font-family: Arial,Helvetica,sans-serif;">Code ||~ <span style="font-family: Arial,Helvetica,sans-serif;">Sensor ||~ <span style="font-family: Arial,Helvetica,sans-serif;">Open circuit ||~ <span style="font-family: Arial,Helvetica,sans-serif;">Short circuit ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">Defrost icon || <span style="font-family: Arial,Helvetica,sans-serif;">Ambient sensor || <span style="font-family: Arial,Helvetica,sans-serif;">Less than -70ºC(94ºF) || <span style="font-family: Arial,Helvetica,sans-serif;">Greater than 141ºC(286ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">Upper vent icon || <span style="font-family: Arial,Helvetica,sans-serif;">Cabin upper sensor || <span style="font-family: Arial,Helvetica,sans-serif;">Less than -38ºC(-36ºF) || <span style="font-family: Arial,Helvetica,sans-serif;">Greater than 141ºC(286ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">Lower vent icon || <span style="font-family: Arial,Helvetica,sans-serif;">Cabin lower sensor || <span style="font-family: Arial,Helvetica,sans-serif;">Less than -38ºC(-36ºF) || <span style="font-family: Arial,Helvetica,sans-serif;">Greater than 141ºC(286ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">0 Fan & Def/lower vent icon*1 || <span style="font-family: Arial,Helvetica,sans-serif;">DEF duct sensor || <span style="font-family: Arial,Helvetica,sans-serif;">Less than -38ºC(-36ºF) || <span style="font-family: Arial,Helvetica,sans-serif;">Greater than 141ºC(286ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">0 Fan & Upper vent icon || <span style="font-family: Arial,Helvetica,sans-serif;">VENT duct sensor || <span style="font-family: Arial,Helvetica,sans-serif;">Less than -38ºC(-36ºF) || <span style="font-family: Arial,Helvetica,sans-serif;">Greater than 141ºC(286ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">0 Fan & Upper/lower vent icon*2 || <span style="font-family: Arial,Helvetica,sans-serif;">Lower duct sensor || <span style="font-family: Arial,Helvetica,sans-serif;">Less than -38ºC(-36ºF) || <span style="font-family: Arial,Helvetica,sans-serif;">Greater than 141ºC(286ºF) ||
 * <span style="font-family: Arial,Helvetica,sans-serif;">1/4 Fan and Def icon || <span style="font-family: Arial,Helvetica,sans-serif;">Sunload sensor || <span style="font-family: Arial,Helvetica,sans-serif;">Open circuit can not be detected w/ self diagnostic || <span style="font-family: Arial,Helvetica,sans-serif;">Greater than 1.784kW (1,534kcal/h, 6,087BTU/h)/m²
 * 1 One chart in the service manual shows 0 fan with Def/lower vent icon, while another shows 0 fan with Def icon alone.
 * 2 One chart in the service manual shows 0 fan with Upper/lower vent icon, while another shows 0 fan with Lower icon alone.

=Related Articles= Air Conditioning System (Category) How-To Guides (Category)