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.

DIAGNOSTIC PROCEDURE

Step	Inspection		Action
1	VERIFY FRONT BODY CONTROL MODULE (FBCM) DTCs AGAIN Clear the DTC for the front body control module (FBCM) using the M-MDS. (See CLEARING DTC [FRONT BODY CONTROL MODULE (FBCM)] .) Retrieve the front body control module (FBCM) DTCs using the M-MDS. (See DTC INSPECTION [FRONT BODY CONTROL MODULE (FBCM)] .) Is the same DTC displayed?	Yes	Go to the next step.
1		No	Go to Step 20.
2	DETERMINE MALFUNCTIONING LIGHT Operate the turn switch to the LH position. Are there any lights among the following which do not flash or continue to be illuminated? Front turn light (LH) Side turn light (LH) (With side turn light) Rear turn light (LH)	Yes	All lights do not flash or continue to be illuminated: Go to the next step. Front turn light (LH) do not flash or continue to be illuminated: Go to Step 4. Side turn light (LH) (With side turn light) and rear turn light (LH) do not flash or continue to be illuminated: Go to Step 10.
2		No	Go to Step 19.
3	INSPECT FRONT BODY CONTROL MODULE (FBCM) 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 front body control module (FBCM) connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to Step 19.
3		No	Repair or replace the connector, then go to Step 19.
4	INSPECT FRONT TURN LIGHT BULB (LH) Inspect the front turn light bulb (LH). Is the bulb normal?	Yes	Go to the next step.
4		No	Replace the bulb, then go to Step 19. (See FRONT TURN LIGHT BULB REMOVAL/INSTALLATION .)
5	INSPECT FRONT TURN LIGHT (LH) 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 front turn light (LH) connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to the next step.
5		No	Repair or replace the connector, then go to Step 19.
6	INSPECT FOR OPEN CIRCUIT IN FRONT TURN LIGHT (LH) GROUND CIRCUIT Verify that the front turn light (LH) connector is disconnected. Inspect for continuity between front turn light (LH) terminal B (wiring harness-side) and body ground. 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 front turn light (LH) terminal B and body ground. 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 19.
7	INSPECT FRONT BODY CONTROL MODULE (FBCM) CONNECTOR CONDITION Disconnect the front body control module (FBCM) connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to the next step.
7		No	Repair or replace the connector, then go to Step 19.
8	INSPECT FOR SHORT TO POWER SUPPLY IN FRONT TURN LIGHT (LH) CONTROL CIRCUIT Verify that the front turn light (LH) and front body control module (FBCM) connectors are disconnected. Reconnect 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 front body control module (FBCM) terminal 2B (wiring harness-side). Is the voltage 0 V?	Yes	Go to the next step.
8		No	Refer to the wiring diagram and verify whether or not there is a common connector between front turn light (LH) terminal A and front body control module (FBCM) terminal 2B. 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 19.
9	INSPECT FOR OPEN CIRCUIT IN FRONT TURN LIGHT (LH) CONTROL CIRCUIT Verify that the front turn light (LH) and front body control module (FBCM) connectors are disconnected. Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Inspect for continuity between front turn light (LH) terminal A (wiring harness-side) and front body control module (FBCM) terminal 2B. Is there continuity?	Yes	Go to Step 19.
9		No	Refer to the wiring diagram and verify whether or not there is a common connector between front turn light (LH) terminal A and front body control module (FBCM) terminal 2B. 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 19.
10	INSPECT REAR TURN LIGHT BULB (LH) Inspect the rear turn light bulb (LH). Is the rear turn light bulb (LH) normal?	Yes	Go to the next step.
10		No	Replace the rear turn light bulb (LH), then go to Step 19. (See REAR TURN LIGHT BULB REMOVAL/INSTALLATION .)
11	INSPECT REAR TURN LIGHT (LH) 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 rear turn light (LH) connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to the next step.
11		No	Repair or replace the connector, then go to Step 19.
12	INSPECT FOR OPEN CIRCUIT IN REAR TURN LIGHT (LH) GROUND CIRCUIT Verify that the rear turn light (LH) connector is disconnected. Inspect for continuity between rear turn light (LH) terminal B (wiring harness-side) and body ground. Is there continuity?	Yes	With side turn light Go to the next step. Without side turn light Go to Step 16.
12		No	Refer to the wiring diagram and verify whether or not there is a common connector between rear turn light (LH) terminal B and body ground. 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 19.
13	INSPECT POWER OUTER MIRROR (LH) CONNECTOR CONDITION Disconnect the power outer mirror (LH) connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to the next step.
13		No	Repair or replace the connector, then go to Step 19.
14	INSPECT SIDE TURN LIGHT (LH) Inspect the side turn light (LH). (See SIDE TURN LIGHT INSPECTION .) Is the side turn light (LH) normal?	Yes	Go to the next step.
14		No	Replace the power outer mirror (LH), then go to Step 19. (See POWER OUTER MIRROR REMOVAL/INSTALLATION .) (See SIDE TURN LIGHT REMOVAL/INSTALLATION .)
15	INSPECT FOR OPEN CIRCUIT IN SIDE TURN LIGHT (LH) GROUND CIRCUIT Verify that the power outer mirror (LH) connector is disconnected. Inspect for continuity between power outer mirror (LH) terminal G (wiring harness-side) and body ground. Is there continuity?	Yes	Go to the next step.
15		No	Refer to the wiring diagram and verify whether or not there is a common connector between power outer mirror (LH) terminal G and body ground. 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 19.
16	INSPECT FRONT BODY CONTROL MODULE (FBCM) CONNECTOR CONDITION Disconnect the front body control module (FBCM) connector. Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection. Is the connector normal?	Yes	Go to the next step.
16		No	Repair or replace the connector, then go to Step 19.
17	INSPECT FOR SHORT TO POWER SUPPLY IN TURN LIGHT (LH) CONTROL CIRCUIT Verify that the side turn light (LH) (With side turn light), rear turn light (LH) and front body control module (FBCM) connectors are disconnected. Reconnect 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 front body control module (FBCM) terminal 2D (wiring harness-side). Is the voltage 0 V?	Yes	Go to the next step.
17		No	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: Rear turn light (LH) terminal A-Front body control module (FBCM) terminal 2D Power outer mirror (LH) terminal E- Front body control module (FBCM) terminal 2D (With side turn light) 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 19.
18	INSPECT FOR OPEN CIRCUIT IN TURN LIGHT (LH) CONTROL CIRCUIT Verify that the side turn light (LH) (With side turn light), rear turn light (LH) and front body control module (FBCM) connectors are disconnected. Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Inspect for continuity between the following terminals (wiring harness-side): Rear turn light (LH) terminal A-Front body control module (FBCM) terminal 2D Power outer mirror (LH) terminal E-Front body control module (FBCM) terminal 2D (With side turn light) Is there continuity?	Yes	Go to the next step.
18		No	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: Rear turn light (LH) terminal A-Front body control module (FBCM) terminal 2D Power outer mirror (LH) terminal E- Front body control module (FBCM) terminal 2D (With side turn light) 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.
19	VERIFY THAT REPAIRS HAVE BEEN COMPLETED Always reconnect all disconnected connectors. Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Clear the DTC for the front body control module (FBCM) using the M-MDS. (See CLEARING DTC [FRONT BODY CONTROL MODULE (FBCM)] .) Retrieve the front body control module (FBCM) DTCs using the M-MDS. (See DTC INSPECTION [FRONT BODY CONTROL MODULE (FBCM)] .) Is the same DTC displayed?	Yes	Repeat the inspection from Step 1. If the malfunction recurs, replace the front body control module (FBCM). (See FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION .) Go to the next step.
19		No	Go to the next step.
20	VERIFY IF OTHER DTCs DISPLAYED Are any other DTCs displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [FRONT BODY CONTROL MODULE (FBCM)] .)
20		No	DTC troubleshooting completed.