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DTC U0301:00 [DSC HU/CM]

id040262011200

Outline

System malfunction location

Brake disc temperature too high

Detection condition

•  The DSC HU/CM detects that the brake disc temperature is high.

Fail-safe

Refer to “DTC Table” and “Fail-safe Function Malfunction Contents Table”.(See DTC TABLE [DSC HU/CM (E)].)

Possible cause

•  Use of frequent braking

•  Continuous Mazda Radar Cruise Control (MRCC) operation

System wiring diagram

Not applicable

Connector diagram

Not applicable

System malfunction location	Brake disc temperature too high
Detection condition	• The DSC HU/CM detects that the brake disc temperature is high.
Fail-safe	Refer to “DTC Table” and “Fail-safe Function Malfunction Contents Table”.(See DTC TABLE [DSC HU/CM (E)].)
Possible cause	• Use of frequent braking • Continuous Mazda Radar Cruise Control (MRCC) operation
System wiring diagram	Not applicable
Connector diagram	Not applicable

Diagnostic Procedure

Step

Inspection

Results

Action

1

INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY

•  Clear the DTC recorded in the memory.
(See CLEARING DTC.)

•  Perform the DTC inspection for the DSC HU/CM.
(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 [(E)].)

If the CAN communication is normal, replace the PCM and perform the repair completion verification.

(See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (E))].)

(See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (E))].)

(See PCM REMOVAL/INSTALLATION [SKYACTIV-D 1.8].)

No

System is normal. (Explain to the customer that a DTC was displayed by an increase in the brake disc temperature due to the use of frequent braking or continuous operation of the Mazda Radar Cruise Control (MRCC).)

Perform the repair completion verification.

Repair completion verification

VERIFY IF OTHER DTCs DISPLAYED

•  Perform the DTC inspection.
(See DTC INSPECTION.)

•  Are any DTCs displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

No

DTC troubleshooting completed.

Step	Inspection	Results	Action
1	INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Perform the DTC inspection for the DSC HU/CM. (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 [(E)].) If the CAN communication is normal, replace the PCM and perform the repair completion verification. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (E))].) (See PCM REMOVAL/INSTALLATION [SKYACTIV-G (WITH CYLINDER DEACTIVATION (E))].) (See PCM REMOVAL/INSTALLATION [SKYACTIV-D 1.8].)
1		No	System is normal. (Explain to the customer that a DTC was displayed by an increase in the brake disc temperature due to the use of frequent braking or continuous operation of the Mazda Radar Cruise Control (MRCC).) Perform the repair completion verification.
Repair completion verification	VERIFY IF OTHER DTCs DISPLAYED • Perform the DTC inspection. (See DTC INSPECTION.) • Are any DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification		No	DTC troubleshooting completed.