ON-BOARD DIAGNOSTIC FUNCTION

id070200100300

Malfunction detection function

• Detects errors in the input and output signals. (The ignition switch is at the ON position or the engine is running.)
• If a malfunction is detected, a DTC is output to the check connector through the malfunction display function. At the same time, malfunction detection results are sent to the fail-safe and memory functions.

Fail-safe function

• If a malfunction is detected by the malfunction detection function and a malfunction is determined, the following controls are performed to prevent an operating malfunction of the full-auto air conditioner and malfunction of output parts.

Fail-safe Function Table

Part where malfunction is determined | Malfunction determined when IG SW at ON | Malfunction already exists when IG SW turned to ON
--- | --- | ---
Cabin temperature sensor | Cabin temperature sensor input value is fixed at 25 °C {77 °F}. | ←
Ambient temperature sensor | Ambient temperature sensor input value is fixed at 15 °C {59 °F}. | ←
Evaporator temperature sensor | Evaporator temperature sensor input value is fixed at 0 °C {32 °F}. | ←
Solar radiation sensor | Solar radiation sensor value is fixed at 0 W/m2. | ←
Air mix actuator (potentiometer) | Air mix actuator drive signal is stopped right when the malfunction is determined. | • The actuators are driven as follows according to the voltage detected at the potentiometer circuit. ― Front air mix actuator (driver’s side) • 0.1 V or less: Driven to HOT • 4.9 V or more: Driven to COLD ― Front air mix actuator (front passenger’s side) • 0.1 V or less: Driven to COLD • 4.9 V or more: Driven to HOT ― Rear air mix actuator • 0.1 V or less: Driven to COLD • 4.9 V or more: Driven to HOT • If the potentiometer circuit voltage is between 0.1 to 4.9 V within 2 s from when the ignition switch is turned to the ON position, the actuator switches to the normal operation. • If the actuator does not switch to the normal operation within 2 s, the actuator drive signal is stopped.
Airflow mode actuator (potentiometer) | Airflow mode actuator drive signal is stopped right when the malfunction is determined. | • The actuators are driven as follows according to the voltage detected at the potentiometer circuit. ― Front airflow mode actuator • 0.1 V or less: Driven to VENT • 4.9 V or more: Driven to DEFROSTER ― Rear airflow mode actuator • 0.1 V or less: Driven to VENT • 4.9 V or more: Driven to HEAT • If the potentiometer circuit voltage is between 0.1 to 4.9 V within 2 s from when the ignition switch is turned to the ON position, the actuator switches to the normal operation. • If the actuator does not switch to the normal operation within 2 s, the actuator drive signal is stopped.
Air mix actuator (motor lock) | Air mix actuator drive signal is stopped right when the malfunction is determined. | After the IG SW is at ON, the air mix actuator drive signal is again output normally.
Airflow mode actuator (motor lock) | Airflow mode actuator drive signal is stopped right when the malfunction is determined. | After the IG SW is at ON, the airflow mode actuator drive signal is again output normally.
Serial communication between the front climate control unit and the rear climate control unit | Preserves the normal data last received until malfunction is repaired. | Disables the communication data (turns off all rear climate control unit switches)
Serial communication between the front climate control unit and the instrument cluster | Inputs the normal data last received until communication is completed. After completing communication, inputs the engine coolant temperature 80 °C {176 °F}and the vehicle speed 0 km/h {0 mph}, and controls the full-auto air conditioner. | Does not turn on the A/C until communication is completed. After communication is completed, inputs the engine coolant temperature 80 °C {176 °F} and the vehicle speed 0 km/h {0 mph}, and controls the full-auto air conditioner.
The front climate control unit receives invalid engine coolant temperature signal data from the instrument cluster | Inputs the correct data last received until reception is completed. After reception is completed, inputs the engine coolant temperature 80 °C {176 °F}, and controls the full-auto air conditioner. | Does not turn on the A/C until reception is completed. After reception is completed, inputs the engine coolant temperature 80 °C {176 °F}, and controls the full-auto air conditioner.

Memory Function

• Stores the signal determined to be malfunctioning by the malfunction detection function, and the memory is not cleared even if the ignition switch is turned off or the malfunction has been repaired.
• To clear stored malfunction information, press the front climate control unit AUTO switch and REC switch simultaneously during past malfunction display mode.

Display Function

• Function for outputting present or past malfunction to the information display as DTCs.

Present Malfunction Display Mode

• Presently occurring malfunctions (open/short circuits) are detected and the DTCs are indicated on the information display.

DTC Table

No. | Output pattern | Malfunction location | Detected condition | Memory function
--- | --- | --- | --- | ---
02 |  | Solar radiation sensor (present malfunction) | Solar radiation sensor (RH) circuit short | —
04 |  | Solar radiation sensor (LH) circuit short | —
06 |  | Cabin temperature sensor (present malfunction) | Cabin temperature sensor circuit open/short circuit | —
10 |  | Front evaporator temperature sensor (present malfunction) | Front evaporator temperature sensor circuit open/short circuit | —
12 |  | Ambient temperature sensor (present malfunction) | Ambient temperature sensor circuit open/short circuit | —
18 |  | Driver-side front air mix actuator (potentiometer) (present malfunction)*1 Passenger-side front air mix actuator (potentiometer) (present malfunction)*2 | Driver-side front air mix actuator (potentiometer) circuit open/short circuit*1 Passenger-side front air mix actuator (potentiometer) circuit open/short circuit*2 | —
21 |  | Front airflow mode actuator (potentiometer) (present malfunction) | Front airflow mode actuator (potentiometer) circuit open/short circuit | —
37 |  | Passenger-side front air mix actuator (potentiometer) (present malfunction)*1 Driver-side front air mix actuator (potentiometer) (present malfunction)*2 | Passenger- side front air mix actuator (potentiometer) circuit open/short circuit*1 Driver-side front air mix actuator (potentiometer) circuit open/short circuit*2 | —
69 |  | Rear climate control unit communication system (present malfunction) | Between front climate control unit and rear climate control unit communication circuit open/short circuit | —
76 |  | Rear air mix actuator (potentiometer) (present malfunction) | Rear air mix actuator (potentiometer) circuit open/short circuit | —
78 |  | Rear evaporator temperature sensor (present malfunction) | Rear evaporator temperature sensor circuit open/short circuit | —
85 |  | Rear airflow mode actuator (potentiometer) (present malfunction) | Rear airflow mode actuator (potentiometer) circuit open/short circuit | —

— :Not applicable
*1 :L.H.D.
*2 :R.H.D.

Past Malfunction Display Mode

• Past occurrence of sensor and other input circuit malfunctions (open/short circuits) are stored and the DTCs indicated on the table are displayed on the information display. Once a past malfunction has been stored and after malfunctioning part has been repaired, the past malfunction will continue to remain in the memory. Therefore, after repairing, clear the past malfunction from the memory.
• To clear stored past malfunction information, press the front climate control unit AUTO switch and REC switch simultaneously during past malfunction display mode.

DTC Table

No. | Output pattern | Malfunction location | Detected condition | Memory function
--- | --- | --- | --- | ---
07 |  | Cabin temperature sensor (past malfunction) | When an open/short has occurred in the cabin temperature sensor circuit 1 time or more in the past | X
11 |  | Front evaporator temperature sensor (past malfunction) | When an open/short has occurred in the front evaporator temperature sensor circuit 1 time or more in the past | X
13 |  | Ambient temperature sensor (past malfunction) | When an open/short has occurred in the ambient temperature sensor circuit 1 time or more in the past | X
19 |  | Driver-side front air mix actuator (potentiometer) (past malfunction)*1 Passenger-side front air mix actuator (potentiometer) (past malfunction)*2 | When an open/short has occurred in the driver-side front air mix actuator (potentiometer) circuit 1 time or more in the past*1 When an open/short has occurred in the passenger-side front air mix actuator (potentiometer) circuit 1 time or more in the past*2 | X
22 |  | Front airflow mode actuator (potentiometer) (past malfunction) | When an open/short has occurred in the front airflow mode actuator (potentiometer) circuit 1 time or more in the past | X
38 |  | Passenger-side front air mix actuator (potentiometer) (past malfunction)*1 Driver-side front air mix actuator (potentiometer) (past malfunction)*2 | When an open/short has occurred in the passenger-side front air mix actuator (potentiometer) circuit 1 time or more in the past*1 When an open/short has occurred in the driver-side front air mix actuator (potentiometer) circuit 1 time or more in the past*2 | X
58 |  | Driver-side front air mix actuator (motor lock) (past malfunction)*1 Passenger-side front air mix actuator (motor lock) (past malfunction)*2 | When motor lock has occurred in the driver-side front air mix actuator circuit 1 time or more in the past*1 When motor lock has occurred in the passenger-side front air mix actuator circuit 1 time or more in the past*2 | X
59 |  | Front airflow mode actuator (motor lock) (past malfunction) | When motor lock has occurred in the front airflow mode actuator circuit 1 time or more in the past | X
61 |  | Passenger-side front air mix actuator (motor lock) (past malfunction)*1 Driver-side front air mix actuator (motor lock) (past malfunction)*2 | When motor lock has occurred in the passenger-side front air mix actuator circuit 1 time or more in the past*1 When motor lock has occurred in the driver-side front air mix actuator circuit 1 time or more in the past*2 | X
68 |  | Rear climate control unit communication system (past malfunction) | When an open/short has occured in the between front climate control unit and rear climate control unit communication circuit 1 time or more in the past | X
77 |  | Rear air mix actuator (potentiometer) (past malfunction) | When an open/short has occurred in the rear air mix actuator (potentiometer) circuit 1 time or more in the past | X
79 |  | Rear evaporator temperature sensor (past malfunction) | When an open/short has occurred in the rear evaporator temperature sensor circuit 1 time or more in the past | X
86 |  | Rear airflow mode actuator (potentiometer) (past malfunction) | When an open/short has occurred in the rear airflow mode actuator (potentiometer) circuit 1 time or more in the past | X
95 |  | Rear air mix actuator (motor lock) (past malfunction) | When motor lock has occurred in the rear air mix actuator circuit 1 time or more in the past | X
96 |  | Rear airflow mode actuator (motor lock) (past malfunction) | When motor lock has occurred in the rear airflow mode actuator circuit 1 time or more in the past | X

X :Applicable
*1 :L.H.D.
*2 :R.H.D.

A/C Operation Check Mode

• The front climate control unit forces operation of output related moving parts as indicated in the operation check table regardless of input related parts, while simultaneously changing the display on the information display as well as illuminating each switch indicator light automatically. A malfunctioning part can be determined by verifying that each transition is as indicated in the operation check table through visual inspection, listening to the operation sound, or placing a hand on the air vent.

Step | Target part | Operation condition | Monitor display*
--- | --- | --- | ---
1 | Front climate control unit |  | Entire illumination of climate control display
Information display |
2 | Blower motor |  | 01
3 | Air mix door |  | 20.0 (0%) 20.5 (50%) 21.0 (100%) 20.5 (50%)
4 | Airflow mode door |  | 03
5 | Air intake door A/C compressor | FRESH Û REC ON Û OFF | 04

* :Shown on the information display (at the set temperature display) according to each step.