How To Display and Read Diagnostic Trouble Codes

CHECKING PROCEDURE





STEP 1: Checks LEDs and segments
- When switch's LED and segments are in good order in STEP 1 mode, the corresponding LED and fluorescent display tube will illuminate.





- If LEDs or segments malfunction, LED does not come on or display shows 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 4 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.

5:

- 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 the above conditions.

Note:
*1: "50%" and "30%" refer to percentage with respect to full stroke of air mix door. (Full cold: 0%, Full hot: 100%)
*2: Conduct self-diagnosis STEP 2 under sunshine.
When conducting indoors, direct light (more than 60W) at sunload sensor.

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 16 seconds to check all mode doors.








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





- If two or more mode 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.
31->32->33->34->35->31->32...
- If intake mode door harness connector is disconnected, the following display pattern will appear.
36->38->39->36->38...

- 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 mode, the auto amplifier will forcefully transmit an output to the affected actuators in response to code No. shown on display, as indicated in table below.








- Checks must be made visually, by listening to any noise, or by touching air outlets with your hand, etc. for improper operation.

Note: Operating condition of each actuator cannot be checked by indicators.

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 returns to original presentation "51".
- If temperature shown on display greatly differs from actual temperature, check sensor circuit at first then inspect sensor itself.

Detects multiplex communication error








- Display shows "52"in STEP 5 mode. (Multiplex communication error between control unit and auto amplifier is detected)

CAUTION:
- The auto amp. memorizes any communication error in the system in a normal control with battery connected. When there is an error, display will be as shown above. When plural errors occur, the display of each error will blink two times for 0.5 second intervals.





- If a communication error is displayed, follow the flow chart above. Determine if the error occurred in the past or is currently happening.





Note:
When battery cable is disconnected, trimmer operation is canceled and temperature set becomes that of initial condition, i.e. 0°C (0°F)

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. 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.

Note: When battery cable is disconnected, trimmer operation is canceled and temperature set becomes that of initial condition, i.e. 0°C (0°F).