DTC B1C1A:12, B1C1A:13, B1C1B:12, B1C1B:13 [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)]

id0702k2818100

System malfunction location	R.H.D.: •  B1C1A:12: Driver-side front air mix actuator (potentiometer) circuit short to power supply •  B1C1A:13: Driver-side front air mix actuator (potentiometer) circuit open •  B1C1B:12: Passenger-side front air mix actuator (potentiometer) circuit short to power supply •  B1C1B:13: Passenger-side front air mix actuator (potentiometer) circuit open L.H.D.: •  B1C1A:12: Passenger-side front air mix actuator (potentiometer) circuit short to power supply •  B1C1A:13: Passenger-side front air mix actuator (potentiometer) circuit open •  B1C1B:12: Driver-side front air mix actuator (potentiometer) circuit short to power supply •  B1C1B:13: Driver-side front air mix actuator (potentiometer) circuit open
Detection condition	•  Malfunction in wiring harness between front air mix actuator and front climate control unit
Fail-safe function	Malfunction determined when ignition switched ON •  Front air mix actuator drive signal is stopped right after the malfunction is determined. ―  However, fixed at MAX COLD when set temperature is at 18.0 °C (64 °F) and fixed at MAX HOT when set temperature is at 32.0 °C (90 °F) Malfunction already exists when ignition switched ON •  Control based on ambient temperature. ―  However, fixed at MAX COLD when set temperature is at 18.0 °C (64 °F) and fixed at MAX HOT when set temperature is at 32.0 °C (90 °F)
Possible cause	R.H.D.: •  Front air mix actuator connector or terminal malfunction •  Front air mix actuator malfunction •  Front climate control unit connector or terminal malfunction •  Front climate control unit malfunction •  Open circuit in wiring harness between the following terminals: Driver-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal C ―  Front climate control unit terminal 2I—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal A Passenger-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal A ―  Front climate control unit terminal 2K—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal C •  Short to power supply in wiring harness between the following terminals: Driver-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal C ―  Front climate control unit terminal 2I—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal A Passenger-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal A ―  Front climate control unit terminal 2K—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal C
Possible cause	L.H.D.: •  Front air mix actuator connector or terminal malfunction •  Front air mix actuator malfunction •  Front climate control unit connector or terminal malfunction •  Front climate control unit malfunction •  Open circuit in wiring harness between the following terminals: Passenger-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal C ―  Front climate control unit terminal 2I—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal A Driver-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal A ―  Front climate control unit terminal 2K—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal C •  Short to power supply in wiring harness between the following terminals: Passenger-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal C ―  Front climate control unit terminal 2I—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal A Driver-side: ―  Front climate control unit terminal 1C—Front air mix actuator terminal A ―  Front climate control unit terminal 2K—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal C

Diagnostic Procedure

STEP	INSPECTION		ACTION
1	INSPECT FRONT AIR MIX ACTUATOR CONNECTOR •  Switch the ignition off. •  Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) •  Disconnect the front air mix actuator connector. (See FRONT AIR MIX ACTUATOR REMOVAL/INSTALLATION.) •  Inspect the connector and terminals (corrosion, damage, pin disconnection). •  Are the connector and terminals normal?	Yes	Go to the next step.
		No	Repair/replace the connector or terminal. After repair procedure, go to Step 6.
2	INSPECT FRONT AIR MIX ACTUATOR •  Inspect the front air mix actuator. (See FRONT AIR MIX ACTUATOR INSPECTION.) •  Is it normal?	Yes	Go to the next step.
		No	Replace the front air mix actuator. (See FRONT AIR MIX ACTUATOR REMOVAL/INSTALLATION.) Go to Step 6.
3	VERIFY FRONT CLIMATE CONTROL UNIT CONNECTOR CONDITION •  Disconnect the front climate control unit connector. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.) •  Inspect the connector and terminals (corrosion, damage, pin disconnection). •  Are the connector and terminals normal?	Yes	Go to the next step.
		No	Repair/replace the connector or terminal. After repair procedure, go to step 6.
4	INSPECT FRONT AIR MIX ACTUATOR (POTENTIOMETER) CIRCUIT FOR OPEN CIRCUIT •  Front climate control unit and front air mix actuator connectors are disconnected. •  Inspect for continuity between the following terminals (wiring harness-side): Driver-side (R.H.D.): ―  Front climate control unit terminal 1C—Front air mix actuator terminal C ―  Front climate control unit terminal 2I—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal A Passenger-side (R.H.D.): ―  Front climate control unit terminal 1C—Front air mix actuator terminal A ―  Front climate control unit terminal 2K—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal C Driver-side (L.H.D.): ―  Front climate control unit terminal 1C—Front air mix actuator terminal A ―  Front climate control unit terminal 2K—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal C Passenger-side (L.H.D.): ―  Front climate control unit terminal 1C—Front air mix actuator terminal C ―  Front climate control unit terminal 2I—Front air mix actuator terminal B ―  Front climate control unit terminal 1Q—Front air mix actuator terminal A •  Is there continuity?	Yes	Go to the next step.
		No	Refer to the wiring diagram and verify whether or not there is a common connector between front climate control unit terminal and front air mix actuator terminal. If there is a common connector: •  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. •  Repair or replace the malfunctioning part. If there is no common connector: •  Repair or replace the wiring harness which has an open circuit. Go to Step 6.
5	INSPECT FRONT AIR MIX ACTUATOR (POTENTIOMETER) SHORT TO POWER SUPPLY •  Front climate control unit and front air mix actuator connectors are disconnected. •  Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) •  Switch the ignition ON (engine off or on). •  Measure the voltage at the following terminals (wiring harness-side): Driver-side (R.H.D.): ―  Front climate control unit terminal 1C ―  Front climate control unit terminal 2I ―  Front climate control unit terminal 1Q Passenger-side (R.H.D.): ―  Front climate control unit terminal 1C ―  Front climate control unit terminal 2K ―  Front climate control unit terminal 1Q Driver-side (L.H.D.): ―  Front climate control unit terminal 1C ―  Front climate control unit terminal 2K ―  Front climate control unit terminal 1Q Passenger-side (L.H.D.): ―  Front climate control unit terminal 1C ―  Front climate control unit terminal 2I ―  Front climate control unit terminal 1Q •  Is the voltage 0 V?	Yes	Go to the next step.
		No	Refer to the wiring diagram and verify whether or not there is a common connector between front climate control unit terminal and front air mix actuator terminal. If there is a common connector: •  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply. •  Repair or replace the malfunctioning part. If there is no common connector: •  Repair or replace the wiring harness which has a short to power supply. Go to the next step.
6	VERIFY THAT SAME DTC IS NOT OUTPUT AGAIN •  Switch the ignition off. •  Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) •  Reconnect the disconnected connectors. •  Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) •  Clear the DTC from the front climate control unit memory using the M-MDS. (See CLEARING DTC [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)].) •  Perform the DTC inspection for the front climate control unit using the M-MDS. (See DTC DISPLAY [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)].) •  Is the same DTC displayed?	Yes	Repeat the inspection from Step 1. •  If the malfunction recurs, replace the front climate control unit. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.) Go to the next step.
		No	Go to the next step.
7	VERIFY THAT NO OTHER DTCs ARE PRESENT •  Verify other DTCs displayed. •  Are any other DTCs displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)].)
		No	DTC troubleshooting completed.