Diagnostic Procedure

WARNING: This page is about a different car, the 2018 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DTC B1143:13 (FRONT BODY CONTROL MODULE (FBCM)) 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)) .) Switch the ignition ON (engine off or on) and wait for 2 s or more. Retrieve the front body control module (FBCM) DTCs using the M-MDS. (See INSPECTION (FRONT BODY CONTROL MODULE (FBCM)) .) Is the same Pending DTC present?	Yes	Go to the next step.
1		No	Go to Step 8.
2	INSPECT START STOP UNIT CONNECTOR Switch the ignition off. Disconnect the negative battery terminal (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .) Disconnect the start stop unit 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.
2		No	Repair or replace the connector, then go to Step 7.
3	INSPECT FRONT BODY CONTROL MODULE (FBCM) CONNECTOR 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.
3		No	Repair or replace the connector, then go to Step 7.
4	INSPECT FOR SHORT TO GROUND IN IG2 RELAY CONTROL CIRCUIT Verify that the start stop unit and front body control module (FBCM) connectors are disconnected. Inspect for continuity between start stop unit terminal 2D (wiring harness-side) and body ground. Is the continuity?	Yes	Refer to the wiring diagram and verify whether or not there is a common connector between start stop unit terminal 2D and front body control module (FBCM) terminal 2U. 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 7.
4		No	Go to the next step.
5	INSPECT FOR OPEN CIRCUIT IN IG2 RELAY CONTROL CIRCUIT Verify that the start stop unit and front body control module (FBCM) connectors are disconnected. Inspect for continuity between start stop unit terminal 2D (wiring harness-side) and front body control module (FBCM) terminal 2U (wiring harness-side). Is the 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 start stop unit terminal 2D and front body control module (FBCM) terminal 2U. 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 START STOP UNIT Inspect the start stop unit. (See START STOP UNIT INSPECTION .) Is the start stop unit normal?	Yes	Go to the next step.
6		No	Replace the start stop unit, then go to the next step. (See START STOP UNIT REMOVAL/INSTALLATION .)
7	VERIFY THAT REPAIRS HAVE BEEN COMPLETED Always reconnect all disconnected connectors. Reconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .) Clear the DTC for the front body control module (FBCM) using the M-MDS. (See CLEARING DTC (FRONT BODY CONTROL MODULE (FBCM)) .) Switch the ignition ON (engine off or on) and wait for 2 s or more. Retrieve the front body control module (FBCM) DTCs using the M-MDS. (See DTC INSPECTION (FRONT BODY CONTROL MODULE (FBCM)) .) Is the same Pending DTC present?	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.
7		No	Go to the next step.
8	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)) .)
8		No	DTC troubleshooting completed.