DTC U0401:68 [VEHICLE CONTROL MODULE]

id1502c5035200

Warning

<<High voltage>>

•  Always observe the following thoroughly to ensure safety when inspecting or removing/installing parts in the motor compartment. Otherwise, the high voltage circuit may operate on the vehicle regardless of whether or not the main power is switched OFF or ON (READY off or on). If this occurs, it could cause electrical shock and result in serious injury or, in the worst case, death.

―  Do not select high voltage battery cooling on center display after EV system stops

―  Do not open/close doors frequently with main power switched OFF

―  Do not perform normal charging or quick charging

―  Switch to connected vehicle maintenance mode (MyMazda App connected vehicle)

―  Cancel climate control timer

―  Operate center display and turn off battery heater operation

Warning

•  The cooling fan may suddenly start operating regardless of the main power switch position. Keep hands and tools away from the cooling fan even if the cooling fan is not operating to prevent injury, or damage to the cooling fan. When servicing the cooling fan or parts near the cooling fan, ensure the following.

―  Do not perform normal charging or quick charging

―  Do not select high voltage battery cooling on center display after EV system stops

―  Do not open/close doors frequently with main power switched OFF

―  Switch to connected vehicle maintenance mode (MyMazda App connected vehicle)

―  Cancel climate control timer

―  Operate center display and turn off battery heater operation

Outline

System malfunction location	Error signal received from PCM, electronically controlled brake unit, instrument cluster, or body control module (BCM)
Detection condition	•  When any of the following conditions is met. ―  The vehicle control module (VCM) receives the following error signal from the PCM for 5 min. •  Accelerator pedal opening angle ―  The vehicle control module (VCM) detects that the brake signals between the following modules did not match for 10 s while the brake pedal is operated. •  PCM •  Electronically controlled brake unit •  Body control module (BCM) ―  The vehicle control module (VCM) detects that a fail-safe is operated based on a deceleration request for 30 min while the vehicle is being driven.
Fail-safe	(See DTC TABLE [VEHICLE CONTROL MODULE (E)].)
Possible cause	•  PCM malfunction ―  Brake switch malfunction ―  Brake fluid pressure sensor malfunction (built into electronically controlled brake unit) ―  Cruise control switch malfunction ―  Accelerator pedal position sensor malfunction •  Electronically controlled brake unit malfunction •  Instrument cluster malfunction •  Vehicle control module (VCM) malfunction (built into body control module (BCM)) •  Body control module (BCM) malfunction
System wiring diagram	Not applicable
Connector diagram	Not applicable

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 (E)].) (See DTC TABLE [BODY CONTROL MODULE (BCM) (E)].)
		No	Go to the next step.
2	INSPECT PCM FOR MALFUNCTION •  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 (e-SKYACTIV)].)
		No	Go to the next step.
3	INSPECT ELECTRONICALLY CONTROLLED BRAKE UNIT FOR MALFUNCTION •  Perform the DTC inspection for the electronically controlled brake unit. (See DTC INSPECTION.) •  Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)
		No	Go to the next step.
4	INSPECT INSTRUMENT CLUSTER FOR MALFUNCTION •  Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION.) •  Is a instrument cluster related DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [BODY CONTROL MODULE (BCM) (E)].)
		No	Go to the next step.
5	INSPECT BODY CONTROL MODULE (BCM) FOR MALFUNCTION •  Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION.) •  Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [BODY CONTROL MODULE (BCM) (E)].)
		No	Go to the next step.
6	INSPECT CRUISE CONTROL SWITCH FOR MALFUNCTION •  Inspect the cruise control switch for a malfunction. (See CRUISE CONTROL SWITCH INSPECTION.) •  Is the cruise control switch normal?	Yes	Replace the cruise control switch and perform the repair completion verification. (See CRUISE CONTROL SWITCH REMOVAL/INSTALLATION.)
		No	Go to the next step.
7	INSPECT PCM 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.) •  Operate the brake pedal. •  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 [L.H.D. (E)].) (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].) If the CAN communication is normal, replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION.)
		No	Go to repair completion verification 2.
8	INSPECT ELECTRONICALLY CONTROLLED BRAKE UNIT 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.) •  Operate the brake pedal. •  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 [L.H.D. (E)].) (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].) If the CAN communication is normal, replace the electronically controlled brake unit and perform the repair completion verification. (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].) (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].)
		No	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.) •  Operate the brake pedal. •  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 [L.H.D. (E)].) (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].) 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.)
		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.
		No	DTC troubleshooting completed.