DTC U0301:00/U0401:00 [DSC HU/CM]

id040262860500

DTC
U0301:00
Signal error from PCM
U0401:00
DETECTION CONDITION
•  Error detected in signal from PCM via CAN communication.
FAIL-SAFE FUNCTION
•  Refer to “Fail-safe function table”. (See DTC TABLE [DSC HU/CM].)
POSSIBLE CAUSE
•  DTCs are stored in the PCM
•  DTCs are stored in the TCM
•  Short to ground or open circuit in backup voltage circuit:
?  Short to ground in wiring harness between MAIN 200 A fuse and PCM terminal 2O
?  MAIN 200 A fuse and/or ROOM 25 A fuse and/or ENG.+BB 7.5 A fuse malfunction
?  Open circuit in wiring harness between battery positive terminal and PCM terminal 2O
•  PCM malfunction
•  TCM malfunction

Diagnostic Procedure

Step

Inspection

Action
1
VERIFY DTCs
•  Using the M-MDS, perform the PCM and TCM DTC inspection.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.5T)].)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (GW6A-EL, GW6AX-EL)].)
DTC troubleshooting completed, then go to the next step.
No
Go to the next step.
2
INSPECT BACKUP VOLTAGE CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
•  Reconnect all disconnected connectors.
•  Access the VPWR PID using the M-MDS.
•  Verify the VPWR PID value.
•  Is the VPWR PID value B+?
Yes
Go to the next step.
No
Inspect the MAIN 200 A fuse, ROOM 25 A fuse and ENG.+BB 7.5 A fuse.
•  If the fuse is blown:
?  Refer to the wiring diagram and verify whether or not there is a common connector between MAIN 200 A fuse and PCM terminal 2O.
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.
•  Replace the malfunctioning fuse.
•  If the fuse is damaged:
?  Replace the malfunctioning fuse.
•  If all fuses are normal:
?  Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and PCM terminal 2O.
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.
3
DETERMINE IF MALFUNCTION IS PCM OR TCM
•  Inspect the PCM.
•  Is the PCM normal?
Yes
Go to the next step.
No
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
4
VERIFY THAT THE SAME DTC IS NOT PRESENT
•  Clear the DTCs from the memory.
•  Are the same DTCs present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the control valve body, then go to the next step
Go to the next step.
No
Go to the next step.
5
VERIFY IF OTHER DTCs DISPLAYED
•  Are any other DTCs displayed?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [DSC HU/CM].)
No
DTC troubleshooting completed.