DTC B1B71:11, B1B71:13 [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] - MAZDA CX-9 TC 2016

DTC B1B71:11, B1B71:13 [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)]

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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	• B1B71:11: Evaporator temperature sensor circuit short to ground • B1B71:13: Evaporator temperature sensor circuit open
Detection condition	• Malfunction in wiring harness between evaporator temperature sensor and front climate control unit
Fail-safe function	• A/C output OFF is controlled when the evaporator temperature sensor input value is at 0 °C {32 °F}.
Possible cause	• Connector or terminal malfunction • Evaporator temperature sensor malfunction • Open circuit in wiring harness between front climate control unit and evaporator temperature sensor • Short to ground in wiring harness between front climate control unit and evaporator temperature sensor • Front climate control unit malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	INSPECT EVAPORATOR TEMPERATURE SENSOR CONNECTOR • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Disconnect the evaporator temperature sensor connector. (See EVAPORATOR TEMPERATURE SENSOR 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 EVAPORATOR TEMPERATURE SENSOR • Inspect the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR INSPECTION.) • Is it normal?	Yes	Go to the next step.
2		No	Replace the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION.) Go to Step 6.
3	INSPECT EVAPORATOR TEMPERATURE SENSOR 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): ? Front climate control unit terminal 1I—evaporator temperature sensor terminal A ? Front climate control unit terminal 1P—evaporator temperature sensor terminal B • 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 evaporator temperature sensor 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 EVAPORATOR TEMPERATURE SENSOR CIRCUIT FOR SHORT TO GROUND • Inspect for continuity between the following terminal (wiring harness-side) and body ground: ? Front climate control unit terminal 1P • Is there continuity?	Yes	Refer to the wiring diagram and verify whether or not there is a common connector between front climate control unit terminal and evaporator temperature sensor 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 ground. • Repair or replace the malfunctioning part. If there is no common connector: • Repair or replace the wiring harness which has a short to ground. Go to Step 6.
4		No	Go to the next step.
5	VERIFY FRONT CLIMATE CONTROL UNIT CONNECTOR CONDITION • 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	• B1B71:11: Evaporator temperature sensor circuit short to ground • B1B71:13: Evaporator temperature sensor circuit open
Detection condition	• Malfunction in wiring harness between evaporator temperature sensor and front climate control unit
Fail-safe function	• A/C output OFF is controlled when the evaporator temperature sensor input value is at 0 °C {32 °F}.
Possible cause	• Connector or terminal malfunction • Evaporator temperature sensor malfunction • Open circuit in wiring harness between front climate control unit and evaporator temperature sensor • Short to ground in wiring harness between front climate control unit and evaporator temperature sensor • Front climate control unit malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	INSPECT EVAPORATOR TEMPERATURE SENSOR CONNECTOR • Switch the ignition off. • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.) • Disconnect the evaporator temperature sensor connector. (See EVAPORATOR TEMPERATURE SENSOR 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 EVAPORATOR TEMPERATURE SENSOR • Inspect the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR INSPECTION.) • Is it normal?	Yes	Go to the next step.
2		No	Replace the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION.) Go to Step 6.
3	INSPECT EVAPORATOR TEMPERATURE SENSOR 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): ? Front climate control unit terminal 1Q—evaporator temperature sensor terminal A ? Front climate control unit terminal 1E—evaporator temperature sensor terminal B • 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 evaporator temperature sensor 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 EVAPORATOR TEMPERATURE SENSOR CIRCUIT FOR SHORT TO GROUND • Inspect for continuity between the following terminal (wiring harness-side) and body ground: ? Front climate control unit terminal 1E • Is there continuity?	Yes	Refer to the wiring diagram and verify whether or not there is a common connector between front climate control unit terminal and evaporator temperature sensor 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 ground. • Repair or replace the malfunctioning part. If there is no common connector: • Repair or replace the wiring harness which has a short to ground. Go to Step 6.
4		No	Go to the next step.
5	VERIFY FRONT CLIMATE CONTROL UNIT CONNECTOR CONDITION • 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.