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 U300E:13 (CLIMATE CONTROL UNIT - FULL-AUTO AIR CONDITIONER) DIAGNOSTIC PROCEDURE - WITH DUAL TYPE CLIMATE CONTROL UNIT

STEP	INSPECTION		ACTION
1	INSPECT FUSE Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Remove the C/U IG1 15 A fuse. Is the fuse normal?	Yes	Install the C/U IG1 15 A fuse, then go to the next step.
1		No	If the fuse is blown: Refer to the wiring diagram and verify whether or not there is a common connector between C/U IG1 15 A fuse and climate control unit 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. Replace the fuse. If the fuse is damaged: Replace the fuse. Then go to Step 7.
2	INSPECT IG1 RELAY FOR MALFUNCTION Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Remove the IG1 relay. (See RELAY LOCATION .) Inspect the IG1 relay. (See RELAY INSPECTION .) Is the IG1 relay normal?	Yes	Go to the next step.
2		No	Replace the IG1 relay, then go to Step 7. (See RELAY LOCATION .)
3	VERIFY CLIMATE CONTROL UNIT CONNECTOR CONDITION Disconnect the climate control unit connector. (See CLIMATE CONTROL UNIT 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.
3		No	Repair/replace the connector or terminal. After repair procedure, go to Step 7.
4	VERIFY FRONT BODY CONTROL MODULE (FBCM) CONNECTOR CONDITION Disconnect the front body control module (FBCM) connector. (See FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION .) Inspect the connector and terminals (corrosion, damage, pin disconnection). Are the connector and terminals normal?	Yes	Go to the next step.
4		No	Repair/replace the connector or terminal. After repair procedure, go to Step 7.
5	INSPECT CLIMATE CONTROL UNIT POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between the following terminals (wiring harness-side): Climate control unit terminal 1D-IG1 relay terminal C Is there continuity?	Yes	Go to the next step.
5		No	Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and IG1 relay 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 7.
6	INSPECT CLIMATE CONTROL UNIT POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between the following terminals (wiring harness-side): Climate control unit terminal 1F-front body control module (FBCM) terminal 1C Is there continuity?	Yes	Go to the next step.
6		No	Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and front body control module (FBCM) 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 the next step.
7	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 DTCs using the M-MDS. Perform the climate control unit DTC inspection 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.
7		No	Go to the next step.
8	VERIFY THAT NO OTHER DTCs ARE PRESENT Verify other DTCs displayed. (See DTC DISPLAY [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] .) Are any other DTCs output?	Yes	Perform the corresponding DTC inspection. (See DTC TABLE [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] .)
8		No	DTC troubleshooting completed.

DTC U300E:13 (CLIMATE CONTROL UNIT - FULL-AUTO AIR CONDITIONER) DIAGNOSTIC PROCEDURE - WITH SINGLE TYPE CLIMATE CONTROL UNIT

STEP	INSPECTION		ACTION
1	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] .) Disconnect the climate control unit connector. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL 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 4.
2	VERIFY FRONT BODY CONTROL MODULE (FBCM) CONNECTOR CONDITION Disconnect the front body control module (FBCM) connector. (See FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION .) Inspect the connector and terminals (corrosion, damage, pin disconnection). Are the connector and terminals normal?	Yes	Go to the next step.
2		No	Repair/replace the connector or terminal. After repair procedure, go to Step 4.
3	INSPECT CLIMATE CONTROL UNIT POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between the following terminals (wiring harness-side): Climate control unit terminal N-front body control module (FBCM) terminal 1C 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 front body control module (FBCM) 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 the next step.
4	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 DTCs using the M-MDS. Perform the climate control unit DTC inspection 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 [MANUAL AIR CONDITIONER] .) Go to the next step.
4		No	Go to the next step.
5	VERIFY THAT NO OTHER DTCs ARE PRESENT Verify other DTCs displayed. (See DTC DISPLAY [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] .) Are any other DTCs output?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] .)
5		No	DTC troubleshooting completed.