DTC

U0301:00, U0401:00

Abnormal message from PCM

DETECTION CONDITION

• Correct data cannot be received from PCM

FAIL-SAFE FUNCTION

• C0301:00

• Illuminates the TCS/DSC indicator light*³, and master warning light*¹*³.

• Tire pressure monitoring system warning light illuminates after flashes*³.

• Inhibits the TCS*⁴, Hill Launch Assist (HLA)*⁴, vehicle roll prevention function*²*⁴, DSC*⁴, Mazda Radar Cruise Control (MRCC)*²*⁴, Smart City Brake Support (SCBS)*²*⁴, and TPMS*⁴ controls.

• C0401:00

• Illuminates the TCS/DSC indicator light*³ and master warning light*¹*³.

• Inhibits the TCS*⁴, Hill Launch Assist (HLA)*⁴, vehicle roll prevention function*²*⁴, DSC*⁴, Mazda Radar Cruise Control (MRCC)*²*⁴, and Smart City Brake Support (SCBS)*²*⁴ controls.

*¹: Vehicles with Smart City Brake Support (SCBS).

*²: If equipped.

*³: Not illuminated depending on malfunction content.

*⁴: Control enabled depending on malfunction content.

POSSIBLE CAUSE

• PCM malfunction

SYSTEM WIRING DIAGRAM

Not applicable

STEP

INSPECTION

ACTION

1

• Switch the ignition off.

• Using the M-MDS, perform the DTC inspection for the PCM.

  (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].)

• Are any DTCs detected?

Yes

Go to applicable DTC inspection.

(See DTC TABLE [SKYACTIV-G 2.5].)

No

Go to the next step.

2

• Clear the DTCs from the memory.

  (See ON-BOARD DIAGNOSIS [DYNAMIC STABILITY CONTROL (DSC)].)

• Are the same DTCs present?

Yes

Repeat the inspection from Step 1.

If the malfunction recurs, replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

No

Go to the next step.

3

• Are any other DTCs output?

Yes

Go to the applicable DTC inspection.

(See ON-BOARD DIAGNOSIS [DYNAMIC STABILITY CONTROL (DSC)].)

No

DTC troubleshooting completed.