DTC B1C1A:12, B1C1A:13, B1C1B:12, B1C1B:13 [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] - MAZDA CX-9 TC 2016

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

id0702k2818100

Note

• There are two types of front climate control unit, type A and type B.

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Front Climate Control Unit Type A

System malfunction location (L.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
System malfunction location (R.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 when the malfunction is determined. ? However, fixed at MAX COLD when set temperature is at 15.0 °C (60 °F) and fixed at MAX HOT when set temperature is at 29.0 °C (84 °F) Malfunction already exists when ignition switched ON • Control based on ambient temperature. ? However, fixed at MAX COLD when set temperature is at 15.0 °C (60 °F) and fixed at MAX HOT when set temperature is at 29.0 °C (84 °F)
Possible cause	• Connector or terminal malfunction • Front air mix actuator malfunction • Open circuit in wiring harness between front climate control unit and front air mix actuator • Short to power supply in wiring harness between front climate control unit and front air mix actuator • Front climate control unit malfunction

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.
1		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.
2		No	Replace the front air mix actuator. (See FRONT AIR MIX ACTUATOR REMOVAL/INSTALLATION.) Go to Step 6.
3	INSPECT FRONT AIR MIX ACTUATOR (POTENTIOMETER) CIRCUIT FOR OPEN CIRCUIT • Disconnect the front climate control unit connector. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.) • Inspect for continuity between the following terminals (wiring harness-side): L.H.D. (Driver-side) ? Front climate control unit terminal 1R—front air mix actuator terminal A ? Front climate control unit terminal 1X—front air mix actuator terminal B ? Front climate control unit terminal 1I—front air mix actuator terminal C L.H.D. (Passenger-side) ? Front climate control unit terminal 1I—front air mix actuator terminal A ? Front climate control unit terminal 1M—front air mix actuator terminal B ? Front climate control unit terminal 1R—front air mix actuator terminal C R.H.D. (Driver-side) ? Front climate control unit terminal 1R—front air mix actuator terminal C ? Front climate control unit terminal 1M—front air mix actuator terminal B ? Front climate control unit terminal 1I—front air mix actuator terminal A R.H.D. (Passenger-side) ? Front climate control unit terminal 1I—front air mix actuator terminal C ? Front climate control unit terminal 1X—front air mix actuator terminal B ? Front climate control unit terminal 1R—front air mix actuator terminal A • Is there continuity?	Yes	Go to the next step.
3		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.
4	INSPECT FRONT AIR MIX ACTUATOR (POTENTIOMETER) SHORT TO POWER SUPPLY • 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): L.H.D. (Driver-side) ? Front climate control unit terminal 1R ? Front climate control unit terminal 1X ? Front climate control unit terminal 1I L.H.D. (Passenger-side) ? Front climate control unit terminal 1I ? Front climate control unit terminal 1M ? Front climate control unit terminal 1R R.H.D. (Driver-side) ? Front climate control unit terminal 1R ? Front climate control unit terminal 1M ? Front climate control unit terminal 1I R.H.D. (Passenger-side) ? Front climate control unit terminal 1I ? Front climate control unit terminal 1X ? Front climate control unit terminal 1R • Is the voltage 0 V?	Yes	Go to the next step.
4		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 Step 6.
5	VERIFY FRONT CLIMATE CONTROL UNIT CONNECTOR CONDITION • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Inspect the connector and terminals (corrosion, damage, pin disconnection). • Are the connector and terminals normal?	Yes	Go to the next step.
5		No	Repair/replace the connector or terminal. After repair procedure, go to the next step.
6	VERIFY THAT SAME DTC IS NOT OUTPUT AGAIN • Reconnect the disconnected connectors. • Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Clear the DTC from the climate control unit memory using the M-MDS. (See CLEARING DTC [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)].) • Perform the DTC inspection for the 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.
6		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)].)
7		No	DTC troubleshooting completed.

Front Climate Control Unit Type B

System malfunction location (L.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
System malfunction location (R.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 when the malfunction is determined. ? However, fixed at MAX COLD when set temperature is at 15.0 °C (60 °F) and fixed at MAX HOT when set temperature is at 29.0 °C (84 °F) Malfunction already exists when ignition switched ON • Control based on ambient temperature. ? However, fixed at MAX COLD when set temperature is at 15.0 °C (60 °F) and fixed at MAX HOT when set temperature is at 29.0 °C (84 °F)
Possible cause	• Connector or terminal malfunction • Front air mix actuator malfunction • Open circuit in wiring harness between front climate control unit and front air mix actuator • Short to power supply in wiring harness between front climate control unit and front air mix actuator • Front climate control unit malfunction

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.
1		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.
2		No	Replace the front air mix actuator. (See FRONT AIR MIX ACTUATOR REMOVAL/INSTALLATION.) Go to Step 6.
3	INSPECT FRONT AIR MIX ACTUATOR (POTENTIOMETER) CIRCUIT FOR OPEN CIRCUIT • Disconnect the front climate control unit connector. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.) • Inspect for continuity between the following terminals (wiring harness-side): L.H.D. (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 L.H.D. (Passenger-side) ? Front climate control unit terminal 1Q—front air mix actuator terminal A ? Front climate control unit terminal 2I—front air mix actuator terminal B ? Front climate control unit terminal 1C—front air mix actuator terminal C R.H.D. (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 R.H.D. (Passenger-side) ? Front climate control unit terminal 1Q—front air mix actuator terminal C ? Front climate control unit terminal 2K—front air mix actuator terminal B ? Front climate control unit terminal 1C—front air mix actuator terminal A • Is there continuity?	Yes	Go to the next step.
3		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.
4	INSPECT FRONT AIR MIX ACTUATOR (POTENTIOMETER) SHORT TO POWER SUPPLY • 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): L.H.D. (Driver-side) ? Front climate control unit terminal 1C ? Front climate control unit terminal 2K ? Front climate control unit terminal 1Q L.H.D. (Passenger-side) ? Front climate control unit terminal 1Q ? Front climate control unit terminal 2I ? Front climate control unit terminal 1C R.H.D. (Driver-side) ? Front climate control unit terminal 1C ? Front climate control unit terminal 2I ? Front climate control unit terminal 1Q R.H.D. (Passenger-side) ? Front climate control unit terminal 1Q ? Front climate control unit terminal 2K ? Front climate control unit terminal 1C • Is the voltage 0 V?	Yes	Go to the next step.
4		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 Step 6.
5	VERIFY FRONT CLIMATE CONTROL UNIT CONNECTOR CONDITION • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Inspect the connector and terminals (corrosion, damage, pin disconnection). • Are the connector and terminals normal?	Yes	Go to the next step.
5		No	Repair/replace the connector or terminal. After repair procedure, go to the next step.
6	VERIFY THAT SAME DTC IS NOT OUTPUT AGAIN • Reconnect the disconnected connectors. • Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Clear the DTC from the climate control unit memory using the M-MDS. (See CLEARING DTC [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)].) • Perform the DTC inspection for the 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.
6		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)].)
7		No	DTC troubleshooting completed.