Diagnostic Procedure

WARNING: This page is about a different car, the 2014 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DTC B13AF:62 (FRONT BODY CONTROL MODULE) DIAGNOSTIC PROCEDURE

Step	Inspection		Action
1	INSPECT IF MALFUNCTION CAUSE IS START STOP UNIT OR FRONT BODY CONTROL MODULE (FBCM) Display the start stop unit PID H/L_SW_LOW using the M-MDS. (See PID/DATA MONITOR INSPECTION [START STOP UNIT] .) Verify the PID while operating the light switch. Is the PID displayed normally?	Yes	Go to Step 3.
1		No	Go to the next step.
2	INSPECT LIGHT SWITCH Inspect the light switch. (See LIGHT SWITCH INSPECTION .) Is the light switch normal?	Yes	Replace the start stop unit, then go to Step 7. (See START STOP UNIT REMOVAL/INSTALLATION .)
2		No	Replace the light switch, then go to Step 7. (See LIGHT SWITCH REMOVAL/INSTALLATION .)
3	INSPECT IF MALFUNCTION CAUSE IS FRONT BODY CONTROL MODULE (FBCM) OR WIRING HARNESS Display the front body control module (FBCM) PID H/L_SW_LOW1 using the M-MDS. (See PID/DATA MONITOR INSPECTION [FRONT BODY CONTROL MODULE (FBCM)] .) Verify the PID while operating the light switch. Is the PID displayed normally?	Yes	Go to the next step.
3		No	Perform the CAN malfunction diagnosis flow and inspect the CAN for a malfunction. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW .) If there is no malfunction in the CAN, replace the front body control module (FBCM), then go to Step 7. (See FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION .)
4	INSPECT FOR SHORT TO GROUND BETWEEN START STOP UNIT AND FRONT BODY CONTROL MODULE (FBCM) Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5] .) Disconnect the front body control module (FBCM) connector. Disconnect the start stop unit connector. Inspect for continuity between front body control module (FBCM) terminal 2W (wiring harness-side) and body ground. Is there continuity?	Yes	Refer to the wiring diagram and verify whether or not there is a common connector between start stop unit terminal 1X and front body control module (FBCM) terminal 2W. 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 SHORT TO POWER SUPPLY BETWEEN START STOP UNIT AND FRONT BODY CONTROL MODULE (FBCM) Verify that the front body control module (FBCM) and start stop unit connectors are disconnected. Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5] .) Switch the ignition ON (engine off or on). Measure the voltage at the front body control module (FBCM) terminal 2W (wiring harness-side). Is the voltage 0 V ?	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 1X and front body control module (FBCM) terminal 2W. 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 7.
6	INSPECT FOR OPEN CIRCUIT BETWEEN START STOP UNIT AND FRONT BODY CONTROL MODULE (FBCM) Verify that the front body control module (FBCM) and start stop unit connectors are disconnected. Switch the ignition off. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5] .) Inspect for continuity between start stop unit terminal 1X (wiring harness-side) and front body control module (FBCM) terminal 2W (wiring harness-side). 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 start stop unit terminal 1X and front body control module (FBCM) terminal 2W. 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. Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5] .) Clear the front body control module (FBCM) DTCs using the M-MDS. (See CLEARING DTC [FRONT BODY CONTROL MODULE (FBCM)] .) Switch the ignition ON (engine off or on) and wait for 5 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 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.