DTC U0423:00 [RADAR UNIT]

id1502a6019700

System malfunction location

Error signal received from instrument cluster

Detection condition

•  Communication error between instrument cluster and radar unit

Fail-safe

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

•  Inhibits the smart brake support (SBS) system control

•  Inhibits the distance recognition support system (DRSS) control

Possible cause

•  Instrument cluster malfunction

•  Radar unit malfunction

System wiring diagram

•  Not applicable

System malfunction location	Error signal received from instrument cluster
Detection condition	• Communication error between instrument cluster and radar unit
Fail-safe	• Inhibits the Mazda radar cruise control (MRCC) system control • Inhibits the smart brake support (SBS) system control • Inhibits the distance recognition support system (DRSS) control
Possible cause	• Instrument cluster malfunction • Radar unit malfunction
System wiring diagram	• Not applicable

Diagnostic Procedure

Step

Inspection

Action

1

PERFORM DTC INSPECTION FOR INSTRUMENT CLUSTER

•  Perform the instrument cluster DTC inspection using the M-MDS.
(See DTC INSPECTION [INSTRUMENT CLUSTER].)

•  Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [INSTRUMENT CLUSTER].)

Then go to Step 3.

No

Go to the next step.

2

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 instrument cluster, then go to the next step.

(See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)

No

Go to the next step.

3

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.

4

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 INSTRUMENT CLUSTER • Perform the instrument cluster DTC inspection using the M-MDS. (See DTC INSPECTION [INSTRUMENT CLUSTER].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [INSTRUMENT CLUSTER].) Then go to Step 3.
1		No	Go to the next step.
2	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 instrument cluster, then go to the next step. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
2		No	Go to the next step.
3	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.
3		No	Go to the next step.
4	VERIFY THAT NO OTHER DTCs ARE PRESENT • Verify other DTCs displayed. • Are any other DTCs output?	Yes	Perform the corresponding DTC inspection.
4		No	DTC troubleshooting completed.