DTC U0301:09 [RADAR UNIT]

id1502a6018800

System malfunction location

Error signal received from PCM

Detection condition

•  There is an error in the following signals sent from the PCM.

―  Brake switch signal

―  Cruise control system control signal

Fail-safe

•  Inhibits the Mazda radar cruise control (MRCC) system control

•  Inhibits the smart brake support (SBS) system control^*1

•  Inhibits the distance recognition support system (DRSS) control

^*1: Enabled depending on malfunction content.

Possible cause

•  PCM malfunction

•  DSC HU/CM malfunction

•  Radar unit malfunction

System wiring diagram

•  Not applicable

System malfunction location	Error signal received from PCM
Detection condition	• There is an error in the following signals sent from the PCM. ― Brake switch signal ― Cruise control system control signal
Fail-safe	• Inhibits the Mazda radar cruise control (MRCC) system control • Inhibits the smart brake support (SBS) system control^1 • Inhibits the distance recognition support system (DRSS) control ^1: Enabled depending on malfunction content.
Possible cause	• PCM malfunction • DSC HU/CM malfunction • Radar unit malfunction
System wiring diagram	• Not applicable

Diagnostic Procedure

Step

Inspection

Action

1

PERFORM DTC INSPECTION FOR PCM

•  Perform the PCM DTC inspection using the M-MDS.
(See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

•  Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].)

Then go to Step 4.

No

Go to the next step.

2

PERFORM DTC INSPECTION FOR DSC HU/CM

•  Perform the DSC HU/CM DTC inspection using the M-MDS.
(See DTC INSPECTION [DYNAMIC STABILITY CONTROL (DSC)].)

•  Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [DYNAMIC STABILITY CONTROL (DSC)].)

Then go to Step 4.

No

Go to the next step.

3

PERFORM DTC INSPECTION FOR RADAR UNIT

•  Clear radar unit DTCs using the M-MDS.
(See CLEARING DTC [RADAR UNIT].)

•  Switch the ignition ON (engine on).

•  Perform the radar unit DTC inspection using the M-MDS.
(See DTC INSPECTION [RADAR UNIT].)

•  Is the same DTC present?

Yes

Replace the radar unit, then go to the next step.

(See RADAR UNIT REMOVAL/INSTALLATION.)

No

Go to the next step.

4

VERIFY THAT REPAIRS HAVE BEEN COMPLETED

•  Clear radar unit DTCs using the M-MDS.
(See CLEARING DTC [RADAR UNIT].)

•  Switch the ignition ON (engine on).

•  Perform the radar unit DTC inspection using the M-MDS.
(See DTC INSPECTION [RADAR UNIT].)

•  Is the same DTC present?

Yes

Repeat the inspection from Step 1.

•  If the malfunction does not recur, go to the next step.

•  If the malfunction recurs, replace the radar unit.
(See RADAR UNIT REMOVAL/INSTALLATION.)

Go to the next step.

No

Go to the next step.

5

VERIFY THAT NO OTHER DTCs ARE PRESENT

•  Verify other DTCs displayed.

•  Are any other DTCs output?

Yes

Perform the corresponding DTC inspection.

No

DTC troubleshooting completed.

Step	Inspection		Action
1	PERFORM DTC INSPECTION FOR PCM • Perform the PCM DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5].) Then go to Step 4.
1		No	Go to the next step.
2	PERFORM DTC INSPECTION FOR DSC HU/CM • Perform the DSC HU/CM DTC inspection using the M-MDS. (See DTC INSPECTION [DYNAMIC STABILITY CONTROL (DSC)].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [DYNAMIC STABILITY CONTROL (DSC)].) Then go to Step 4.
2		No	Go to the next step.
3	PERFORM DTC INSPECTION FOR RADAR UNIT • Clear radar unit DTCs using the M-MDS. (See CLEARING DTC [RADAR UNIT].) • Switch the ignition ON (engine on). • Perform the radar unit DTC inspection using the M-MDS. (See DTC INSPECTION [RADAR UNIT].) • Is the same DTC present?	Yes	Replace the radar unit, then go to the next step. (See RADAR UNIT REMOVAL/INSTALLATION.)
3		No	Go to the next step.
4	VERIFY THAT REPAIRS HAVE BEEN COMPLETED • Clear radar unit DTCs using the M-MDS. (See CLEARING DTC [RADAR UNIT].) • Switch the ignition ON (engine on). • Perform the radar unit DTC inspection using the M-MDS. (See DTC INSPECTION [RADAR UNIT].) • Is the same DTC present?	Yes	Repeat the inspection from Step 1. • If the malfunction does not recur, go to the next step. • If the malfunction recurs, replace the radar unit. (See RADAR UNIT REMOVAL/INSTALLATION.) Go to the next step.
4		No	Go to the next step.
5	VERIFY THAT NO OTHER DTCs ARE PRESENT • Verify other DTCs displayed. • Are any other DTCs output?	Yes	Perform the corresponding DTC inspection.
5		No	DTC troubleshooting completed.