Diagnostic Procedure

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

DTC B13AB:12, B13AB:13 (CLIMATE CONTROL UNIT - FULL-AUTO AIR CONDITIONER) DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	INSPECT AIR MIX ACTUATOR CONNECTOR Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Disconnect the air mix actuator connector. (See AIR MIX ACTUATOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .) 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 AIR MIX ACTUATOR Inspect the air mix actuator. (See AIR MIX ACTUATOR INSPECTION [FULL-AUTO AIR CONDITIONER] .) Is it normal?	Yes	Go to the next step.
2		No	Replace the air mix actuator. (See AIR MIX ACTUATOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .) Go to Step 6.
3	INSPECT AIR MIX ACTUATOR (POTENTIOMETER) CIRCUIT FOR OPEN CIRCUIT Disconnect the climate control unit connector. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Inspect for continuity between the following terminals (wiring harness-side): Climate control unit terminal H-air mix actuator terminal E Climate control unit terminal G-air mix actuator terminal F Climate control unit terminal E- air mix actuator terminal G 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 climate control unit terminal and 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 AIR MIX ACTUATOR (POTENTIOMETER) CIRCUIT FOR SHORT TO POWER SUPPLY Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Switch the ignition ON (engine off or on). Measure the voltage at the following terminals (wiring harness-side): Climate control unit terminal H Climate control unit terminal G Climate control unit terminal E 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 climate control unit terminal and 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 CLIMATE CONTROL UNIT CONNECTOR CONDITION Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) 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 cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) 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 climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .) 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.