Introduction and General Description

The self-diagnostic system diagnoses sensors, door motors, blower motor, etc. by system line. Refer to applicable systems (items) for details. Shifting from normal control to the self-diagnostic system is done as follows. Start the engine (turn the ignition switch from "OFF" to "ON"). And press "OFF" switch for at least 5 seconds. The "OFF" switch must be pressed within 5 seconds after starting the engine (ignition switch is turned "ON"). This system will be canceled by either pressing "AUTO" switch or turning the ignition switch "OFF". Shifting from one step to another is accomplished by means of pushing "HOT" or "COLD" switch, as required.

Additionally shifting from STEP 5 to AUXILIARY MECHANISM is accomplished by means of pushing "FAN UP" switch.

Step 1 And 2:

Step 3 And 4:

Step 5:

CHECKING PROCEDURE

HOW TO INTERPRET THE RESULTS

STEP 1: Checks LEDs and segments




When switch's LED and segments are in functioning properly in STEP 1, LED and display will come on.




If LEDs or segments malfunction, LED will not come on or display will show incomplete segment.

STEP 2: Checks each sensor circuit for open or short circuit




Display shows "2" in STEP 2 mode.
When all sensors are in good order, display shows "20".
It takes approximately 25 seconds to check all sensors.




If a sensor is malfunctioning, the corresponding code No. blinks on display. A short circuit is identified by a blinking "-" mark preceding mode number.




If two or more sensors malfunction, corresponding code Nos. respectively blink two times.




Sensors and abnormalities
If a circuit is opened or shorted, display shows its code No. when input corresponds with any of following conditions.

STEP 3: Checks mode and intake door positions




Display shows "3"in STEP 3 mode.
When all doors are in good order, display will then show "30".
It takes approximately 50 seconds to check all mode and intake doors.







When abnormalities are detected, display shows a code No. corresponding with malfunctioning part.




If two or more mode or intake doors are out of order, corresponding code numbers respectively blink two times.




If mode door motor harness connector is disconnected, the following display pattern will appear.




If intake mode door harness connector is disconnected, the following display pattern will appear.
If any mode door motor position switch is malfunctioning, mode door motor will also malfunction.

STEP 4: Checks operation of each actuator




Display shows "41"in STEP 4 mode.
When DEF switch is pressed one time, display shows "42". Thereafter, each time the switch is pressed, display advances one number at a time, up to "46", then returns to "41".







During inspection in STEP 4, the auto amp. will forcefully transmit an output to the affected actuators. The corresponding code Nos. are shown on display as indicated in the table.
Checks must be made visually, by listening to any noise, or by touching air outlets with your hand, etc. for improper operation.

STEP 5: Checks temperature detected by sensors











Display shows "51" in STEP 5 mode.
- When FRONT DEF switch is pressed one time, display shows temperature detected by ambient sensor.
- When FRONT DEF switch is pressed second time, display shows temperature detected by in-vehicle sensor.
- When FRONT DEF switch is pressed third time, display shows temperature detected by intake sensor.
- When FRONT DEF switch is pressed fourth time, display returns to original presentation "51".
If temperature shown on display greatly differs from actual temperature, check sensor circuit at first. Then inspect sensor itself according to the procedures described in Control System Input Component.




AUXILIARY MECHANISM: Temperature setting trimmer
This trimmer compensates for differences between temperature setting (displayed digitally) and temperature felt by driver in a range of ± 3° C (± 6° F).
Operating procedures for this trimmer are as follows:
Starting with STEP 5 under "Self-diagnostic mode", press FAN UP switch to set air conditioning system in auxiliary mode. Display shows "61" in auxiliary mechanism. It takes approximately 3 seconds. Then, press either HOT or COLD switch as desired. Temperature will change at a rate of 0.5° C (1° F) each time a switch is pressed.
When battery cable is disconnected, trimmer operation is canceled and temperature set becomes that of initial condition, i.e. 0° C (0° F).