Diagnostic Procedure

WARNING: This page is about a different car, the 2024 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.

DTC U3003:16 (FRONT BODY CONTROL MODULE) 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 10s 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 DTC displayed?	Yes	Go to the next step.
1		No	Go to Step 8.
2	VERIFY PCM DTCs Retrieve the PCM DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [PCM (VIN Y)] .) (See ON-BOARD DIAGNOSTIC TEST [PCM (VIN L (WITHOUT CYLINDER DEACTIVATION))] .) (See ON-BOARD DIAGNOSTIC TEST [PCM (VIN M (WITH CYLINDER DEACTIVATION))] .) Are any DTCs displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (VIN Y)] .) (See DTC TABLE [PCM (VIN L (WITHOUT CYLINDER DEACTIVATION))] .) (See DTC TABLE [PCM (VIN M (WITH CYLINDER DEACTIVATION))] .)
2		No	Go to the next step.
3	INSPECT BATTERY Inspect the battery. (See BATTERY INSPECTION .) Is the battery normal?	Yes	Go to the next step.
3		No	Recharge or replace the battery, then go to Step 7. (See BATTERY RECHARGING .) (See BATTERY REMOVAL/INSTALLATION [VIN Y] .) (See BATTERY REMOVAL/INSTALLATION [VIN L (WITHOUT CYLINDER DEACTIVATION)] .) (See BATTERY REMOVAL/INSTALLATION [VIN M (WITH CYLINDER DEACTIVATION)] .)
4	INSPECT GENERATOR Inspect the generator. (See GENERATOR INSPECTION [VIN Y] .) (See GENERATOR INSPECTION [VIN L (WITHOUT CYLINDER DEACTIVATION)] .) (See GENERATOR INSPECTION [VIN M (WITH CYLINDER DEACTIVATION)] .) Is the generator normal?	Yes	Go to the next step.
4		No	Replace the generator, then go to Step 7. (See GENERATOR REMOVAL/INSTALLATION [VIN Y] .) (See GENERATOR REMOVAL/INSTALLATION [VIN L (WITHOUT CYLINDER DEACTIVATION)] .) (See GENERATOR REMOVAL/INSTALLATION [VIN M (WITH CYLINDER DEACTIVATION)] .)
5	INSPECT FRONT BODY CONTROL MODULE (FBCM) CONNECTOR CONDITION Switch the ignition off. Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .) 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.
5		No	Repair or replace the connector, then go to Step 7.
6	VERIFY FRONT BODY CONTROL MODULE (FBCM) POWER SUPPLY VOLTAGE Always reconnect all disconnected connectors. Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .) Display the PID VPWR_B using the M-MDS. (See PID/DATA MONITOR INSPECTION [FRONT BODY CONTROL MODULE (FBCM)] .) Is the voltage B+?	Yes	Go to the next step.
6		No	Inspect the INTERIOR1 15 A fuse, ROOM 25 A fuse and HAZARD 25 A fuse. Any fuse is blown: Refer to the wiring diagram and verify whether or not there is a common connector between the following: MAIN 200 A fuse-Front body control module (FBCM) terminal 2A MAIN 200 A fuse-Front body control module (FBCM) terminal 1A MAIN 200 A fuse-Front body control module (FBCM) terminal 1B MAIN 200 A fuse-Front body control module (FBCM) terminal 3K MAIN 200 A fuse-Front body control module (FBCM) terminal 3L 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. Any fuse is damaged: Replace the fuse. All fuses are normal: Refer to the wiring diagram and verify whether or not there is a common connector between the following: Battery positive terminal-Front body control module (FBCM) terminal 2A Battery positive terminal-Front body control module (FBCM) terminal 1A Battery positive terminal-Front body control module (FBCM) terminal 1B Battery positive terminal-Front body control module (FBCM) terminal 3K Battery positive terminal-Front body control module (FBCM) terminal 3L 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 REPAIRS HAVE BEEN COMPLETED Always reconnect all disconnected connectors. Connect 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 10s 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 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.
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.