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 U0338:09 (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)) .) 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	Go to the next step.
1		No	Go to Step 6.
2	VERIFY START STOP UNIT DTCs Retrieve the start stop unit DTCs using the M-MDS. (See DTC INSPECTION [START STOP UNIT] .) Are any DTCs displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [START STOP UNIT] .)
2		No	Go to the next step.
3	INSPECT LIGHT SWITCH Inspect the light switch. (See LIGHT SWITCH INSPECTION .) Is the light switch normal?	Yes	Go to the next step.
3		No	Replace the light switch, then go to Step 5. (See LIGHT SWITCH REMOVAL/INSTALLATION .)
4	PERFORM DTC INSPECTION AND VERIFY START STOP UNIT MALFUNCTION 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 Pending DTC present?	Yes	Replace the start stop unit, then go to the next step. (See START STOP UNIT REMOVAL/INSTALLATION .)
4		No	Go to Step 6.
5	VERIFY THAT REPAIRS HAVE BEEN COMPLETED 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 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.
5		No	Go to the next step.
6	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)) .)
6		No	DTC troubleshooting completed.