Diagnostic Procedure

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

DTC B14F4:16 (VEHICLE CONTROL MODULE - US) DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	INSPECT VEHICLE CONTROL MODULE (VCM) AND BODY CONTROL MODULE (BCM) FOR MALFUNCTION Perform the DTC inspection for the vehicle control module (VCM) and the body control module (BCM). (See DTC INSPECTION .) Is a DTC related to an internal malfunction displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [VEHICLE CONTROL MODULE (US)] .) (See DTC TABLE [BODY CONTROL MODULE (BCM) (US)] .)
1		No	Go to the next step.
2	INSPECT PARKING ASSIST UNIT (ULTRASONIC) FOR MALFUNCTION Perform the DTC inspection for the parking assist unit (ultrasonic). (See DTC INSPECTION .) Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PARKING ASSIST UNIT (ULTRASONIC) (US)] .)
2		No	Go to the next step.
3	VERIFY PCM DTCs Perform the DTC inspection for the PCM. (See DTC INSPECTION .) Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (SKYACTIV-G (US))] .)
3		No	Go to the next step.
4	INSPECT PARKING ASSIST UNIT (ULTRASONIC) POWER SUPPLY VOLTAGE Reconnect all the disconnected connectors. Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .) Measure the voltage at parking assist unit (ultrasonic) terminal 1Y. Is the voltage 8 V or less?	Yes	Go to the next step.
4		No	Go to Step 9.
5	INSPECT BATTERY FOR MALFUNCTION Inspect the applicable part. (See BATTERY INSPECTION (US) .) Is the part normal?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See BATTERY RECHARGING (US) .) (See BATTERY REMOVAL/INSTALLATION (VIN L) .) (See BATTERY REMOVAL/INSTALLATION (VIN M) .)
6	INSPECT GENERATOR FOR MALFUNCTION Inspect the applicable part. (See GENERATOR INSPECTION (VIN L) .) (See GENERATOR INSPECTION (VIN M) .) Is the part normal?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See GENERATOR REMOVAL/INSTALLATION (VIN L) .) (See GENERATOR REMOVAL/INSTALLATION (VIN M) .)
7	INSPECT PARKING ASSIST UNIT (ULTRASONIC) CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .) Are the connector and terminal normal?	Yes	Go to the next step.
7		No	Repair or replace the malfunctioning location and perform the repair completion verification.
8	INSPECT IG1 RELAY No. 1 FOR MALFUNCTION Inspect the applicable part. (See RELAY INSPECTION .) Is the part normal?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See RELAY LOCATION (US) .)
9	INSPECT IG1 RELAY No. 1 POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT Inspect the applicable circuit for a short to ground and an open circuit. (See CIRCUIT INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning location and perform the repair completion verification.
10	INSPECT PARKING ASSIST UNIT (ULTRASONIC) POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT Inspect the applicable circuit for a short to ground and an open circuit. (See CIRCUIT INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
10		No	Repair or replace the malfunctioning location and perform the repair completion verification.
11	INSPECT PARKING ASSIST UNIT (ULTRASONIC) FOR MALFUNCTION DEPENDING ON REPEATABILITY Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the vehicle control module (VCM). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, replace the parking assist unit (ultrasonic) and perform the repair completion verification. (See PARKING ASSIST UNIT (ULTRASONIC) REMOVAL/INSTALLATION .)
11		No	Perform the [ACTION FOR NON-REPEATABLE MALFUNCTIONS]. (See TROUBLESHOOTING PROCEDURE (US) .) If DTC is displayed Repeat the diagnosis from Step 1. If DTC is not displayed Go to repair completion verification 2.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the vehicle control module (VCM). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, perform the diagnosis from Step 1. If the malfunction recurs, replace the body control module (BCM), then go to the next step. (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION (US) .)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTC IS DISPLAYED Perform the DTC inspection. (See DTC INSPECTION .) Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.