DTC U0401:68 [DC-DC CONVERTER (e-SKYACTIV)]

id300205059300

Warning

<<High voltage>>

•  If the necessary measures are not taken before servicing an electric vehicle, it could cause electrical shock and result in serious injury or, in the worst case, death. Before servicing the electric vehicle, refer to [HIGH VOLTAGE SERVICE CAUTIONS] in the general information and implement the necessary measures. (See HIGH VOLTAGE SERVICE CAUTIONS.)

Outline

System malfunction location	CAN communication: Error signal received (PT-LOCAL)
Detection condition	•  The DC-DC converter receives an error signal from the PCM via CAN.
Fail-safe	•  Maintains the current DC-DC converter output.
Possible cause	•  CAN communication line malfunction between PCM and DC-DC converter (PT-LOCAL) •  DC-DC converter connector or terminals malfunction •  PCM connector or terminals malfunction •  PCM malfunction •  DC-DC converter malfunction

Diagnostic Procedure

Warning

<<High voltage>>

•  If necessary measures such as wearing the correct protective gear are not taken when inspecting or removing/installing the high voltage parts, it could cause electrical shock and result in serious injury or, in the worst case, death.

•  Before inspecting or removing/installing the high voltage parts, refer to [HIGH VOLTAGE SERVICE CAUTIONS] in the general information and [High Voltage Part Inspection and Removal/Installation Notes] of the high voltage system service cautions and implement the necessary measures and preparations. (See HIGH VOLTAGE SERVICE CAUTIONS.) (See HIGH VOLTAGE SYSTEM SERVICE CAUTIONS.)

Step	Inspection	Results	Action
1	RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION •  Record the snapshot data. Note •  Recording can be facilitated using the screen capture function of the PC.	—	Go to the next step.
2	INSPECT FOR OTHER RELATED DTCs •  Perform the DTC inspection for the DC-DC converter. (See DTC INSPECTION.) •  Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [DC-DC CONVERTER (e-SKYACTIV)].)
		No	Go to the next step.
3	VERIFY PCM DTC •  Perform the DTC inspection for the PCM. (See DTC INSPECTION.) •  Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [PCM (e-SKYACTIV)].)
		No	Go to the next step.
4	INSPECT DC-DC CONVERTER CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
5	INSPECT PCM CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED Warning <<High voltage>> •  Wear insulated gloves when working on a high voltage system. •  Install/connect the part removed/disconnected during the troubleshooting procedure. •  Clear the DTC recorded in the memory. (See CLEARING DTC.) •  Replicate the vehicle conditions at the time the DTC was detected using the following procedure. Warning •  While performing this step, always operate the vehicle in a safe and lawful manner. •  When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. ―  Drive the vehicle under the snapshot data condition. •  Perform the DTC inspection for the DC-DC converter. (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 DC-DC converter, then go to the next step. (See DC-DC CONVERTER REMOVAL/INSTALLATION.)
		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs 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.