System malfunction location

Brake light signal malfunction

Detection condition

• The vehicle control module detects that the brake switch signal and the brake light on/off are incompatible.

Fail-safe

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

• Inhibits the forward obstruction warning (FOW) system control

Possible cause

• Brake light unit malfunction

• Malfunction in circuit between brake light unit and rear body control module (RBCM) and rear body control module (RBCM)

• Brake switch malfunction

• Signal error in circuit between rear body control module (RBCM) and instrument cluster

• Signal error in circuit between instrument cluster and vehicle control module (V/C-module)

• Vehicle control module (V/C-module) malfunction

System wiring diagram

• Not applicable

Step

Inspection

Action

1

• Perform the rear body control module (RBCM) DTC inspection using the M-MDS.

  (See DTC INSPECTION [REAR BODY CONTROL MODULE (RBCM)].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [REAR BODY CONTROL MODULE (RBCM)].)

Then go to Step 5.

No

Go to the next step.

2

• Inspect the brake switch.

  (See BRAKE SWITCH INSPECTION.)

• Is it normal?

Yes

Go to the next step.

No

Replace the brake switch, then go to the Step 5.

(See BRAKE PEDAL REMOVAL/INSTALLATION.)

3

• 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 5.

No

Go to the next step.

4

• Perform the vehicle control module (V/C-module) DTC inspection using the M-MDS.

  (See DTC INSPECTION [VEHICLE CONTROL MODULE (V/C-MODULE)].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [VEHICLE CONTROL MODULE (V/C-MODULE)].)

Then go to the next step.

No

Go to the next step.

5

• Clear vehicle control module (V/C-module) DTCs using the M-MDS.

  (See CLEARING DTC [VEHICLE CONTROL MODULE (V/C-MODULE)].)

• Switch the ignition ON (engine on).

• Drive the vehicle at 40 km/h (25 mph) or more for 3 min or more.

• Perform the vehicle control module (V/C-module) DTC inspection using the M-MDS.

  (See DTC INSPECTION [VEHICLE CONTROL MODULE (V/C-MODULE)].)

• 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 vehicle control module (V/C-module).

  (See VEHICLE CONTROL MODULE (V/C-MODULE) REMOVAL/INSTALLATION [MAZDA RADAR CRUISE CONTROL (MRCC) SYSTEM].)

Go to the next step.

No

Go to the next step.

6

• Verify other DTCs displayed.

• Are any other DTCs output?

Yes

Perform the corresponding DTC inspection.

No

DTC troubleshooting completed.