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Home >> Mazda >> 2021 >> CX-5 Signature >> Repair and Diagnosis >> Brakes >> Traction Control >> On-Board Diagnostic - Dynamic Stability Control System >> DTC U0401-00: ABNORMAL MESSAGE FROM PCM [DSC HU/Control Module] >> Diagnostic procedure

Diagnostic procedure

STEP INSPECTION RESULTS ACTION
1 INSPECT FOR PCM, TCM MALFUNCTION
 
Yes
Go to applicable DTC inspection.
(See DTC TABLE [PCM (VIN M)] .)
(See DTC TABLE [PCM (VIN Y)] .)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (FW6A-EL, FW6AX-EL)] .)
(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [TCM (GW6A-EL, GW6AX-EL)] .)
No VIN Y
  • Go to the next step. VIN M
  • Go to Step 3
2 INSPECT BACKUP VOLTAGE CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
Yes Go to Step 4.
No Inspect the MAIN 200 A fuse and ENG.+B 7.5 A fuse.
  • If the fuse is burnt out:
    • 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 Step 4.
3 INSPECT BACKUP VOLTAGE CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
Yes Go to the next step.
No Inspect the MAIN 200 A fuse and ENG.+B 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 2A.

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 2A.

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.
4 DETERMINE IF MALFUNCTION IS PCM, TCM
Yes Go to the next step.
No Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [VIN M] .)
(See PCM REMOVAL/INSTALLATION [VIN Y] .)
5 VERIFY THAT THE SAME DTC IS NOT PRESENT
Yes Repeat the inspection from Step 1.

Go to the next step.
No Go to the next step.
6 VERIFY IF OTHER DTCs DISPLAYED
  • Are any other DTCs displayed?
 
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [DSC HU/Control Module] .)
No DTC troubleshooting completed.