Mazda 3 Service Manual: No.6 Bsm Indicator Light Flashes While Not Under Bsm Indicator Light Flashing Conditions (No Combination Switch Operation (Turn Signal Switch)) [Blind Spot Monitoring (Bsm)]

6

BSM indicator light flashes while not under BSM indicator light-flashing conditions (no combination switch operation (turn signal switch)

Description

• The BSM indicator light flashes despite not satisfying the BSM indicator light flashing conditions (vehicle speed above 32 km/h {20 mph} or more, turn signal on, and vehicle in warning zone)).

• The BSM indicator light flashes, but the turn signals are off.

Possible Causes

NOTE:

• This malfunction symptom is basically the same as symptom “No.4 BSM indicator light while not under BSM indicator light-illumination conditions”.

• BSM control module recognizes a vehicle as being inside the warning zone when it is actually outside of it.

• Radar (BSM control module integrated) is emitted outside of warning zone (deviates from warning zone)

• Damage, deformity or looseness to installation bracket or vehicle frame (including moderate impacts).

• Malfunction in steering angle signal (communication error between BCM and BSM control module, or steering angle sensor malfunction).

• Problem with rear bumper such as soiling to radar emitting/receiving area, application of stickers (including transparent types), repairs using putty application.

• After-market electrical parts interfere with BSM system

• BSM does not recognize vehicle speed correctly (BSM control module mistakenly recognizes vehicle speed as being above 32 km/h {20 mph} or more

• PCM communication error with BSM control module

• Malfunction in ABS wheel speed sensor related parts

• BSM control module mistakenly recognizes that turn signals have been operated

• Short to ground circuit in wiring harness between combination switch (turn signal switch) and BCM

• Communication error between BCM and BSM control module

• BSM control module malfunction

Step

Inspection

Result

Action

1

VERIFY MALFUNCTION SYMPTOM

• BSM indicator light illuminates while under light-off conditions.

Yes

Go to the symptom troubleshooting procedure, “No.4 BSM indicator light illuminates while not under BSM indicator light-off conditions”.

(See NO.4 BSM INDICATOR LIGHT ILLUMINATES WHILE NOT UNDER LIGHT-ILLUMINATION CONDITIONS [BLIND SPOT MONITORING (BSM)].)

No

Go to the next step.

2

VERIFY DTCs

• Retrieve DTCs from the BSM control module, BCM, DSC HU/CM, PCM, and TCM using the M-MDS.

  (See DTC INSPECTION [BLIND SPOT MONITORING (BSM)].)

  (See DTC INSPECTION [BCM].)

  (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0, MZR 2.5].)

  (See ON-BOARD DIAGNOSTIC TEST [MZR 2.3 DISI Turbo].)

  (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.0].)

  (See ON-BOARD DIAGNOSTIC SYSTEM DTC INSPECTION [FW6A-EL].)

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

• Are any DTCs displayed?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [BLIND SPOT MONITORING (BSM)].)

(See DTC TABLE [BCM].)

(See DTC TABLE [MZR 2.0, MZR 2.5].)

(See DTC TABLE [MZR 2.3 DISI Turbo].)

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

(See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE [FW6A-EL].)

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

No

Go to the next step.

3

INSPECT IF MALFUNCTION IS IN BCM INPUT SIGNAL OR BSM

• Monitor the following PIDs on the suspected side of the BSM control module using the M-MDS.

  (See PID/DATA MONITOR INSPECTION [BCM].)

• TURN_SW_L

• TURN_SW_R

• Are the monitoring values normal?

Yes

Replace the BSM control module.

(See BLIND SPOT MONITORING (BSM) CONTROL MODULE REMOVAL/INSTALLATION.)

No

Go to the next step.

4

INSPECT TURN SIGNAL SWITCH SIGNAL

• Monitor the following BCM PIDs using the M-MDS:

  (See PID/DATA MONITOR INSPECTION [BCM].)

• TURN_SW_L

• TURN_SW_R

• Are the monitoring values normal?

Yes

Replace the BSM control module.

(See BLIND SPOT MONITORING (BSM) CONTROL MODULE REMOVAL/INSTALLATION.)

No

• Inspect the following. If a malfunction is detected, repair or replace the malfunctioning part.

• Combination switch (turn signal switch)

  (See LIGHT SWITCH REMOVAL/INSTALLATION.)

• Wiring harness between combination switch (turn signal switch) and BCM for short to ground circuit

• If a malfunction is not detected, replace the BCM.

  (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION.)