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DTC B1048:7B [BCM]

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2016 – MX-5 – Body and Accessories

DTC B1048:7B [BCM]

Description

Brake fluid level sensor circuit malfunction

Detection condition

  • BCM detected that the brake fluid level is less than MIN with the ignition switched ON (engine off or on).

Fail-safe

Not applicable

Possible cause

  • Insufficient brake fluid level

  • Brake fluid level sensor connector or terminal malfunction

  • BCM connector or terminal malfunction

  • Short to ground in wiring harness between brake fluid level sensor terminal A and BCM terminal 3R

  • Brake fluid level sensor malfunction

  • BCM malfunction

Diagnostic Procedure

Step

Inspection

Action

1

VERIFY BCM DTCs AGAIN

Yes

Go to the next step.

No

Go to Step 8.

2

INSPECT BRAKE FLUID LEVEL

Yes

Go to the next step.

No

Add genuine brake fluid, then go to Step 7.

3

INSPECT BRAKE FLUID LEVEL SENSOR CONNECTOR CONDITION

  • Switch the ignition off.

  • Disconnect the negative battery cable.

    (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

  • Disconnect the brake fluid level sensor connector.

  • Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.

  • Is the connector normal?

Yes

Go to the next step.

No

Repair or replace the connector, then go to Step 7.

4

INSPECT BCM CONNECTOR CONDITION

  • Disconnect the BCM connector.

  • Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.

  • Is the connector normal?

Yes

Go to the next step.

No

Repair or replace the connector, then go to Step 7.

5

INSPECT BRAKE FLUID LEVEL SENSOR SIGNAL CIRCUIT FOR SHORT TO GROUND

  • Verify that the brake fluid level sensor and BCM connectors are disconnected.

  • Inspect for continuity between BCM terminal 3R (wiring harness-side) and body ground.

  • Is there continuity?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between brake fluid level sensor terminal A and BCM terminal 3R.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to ground.

Go to Step 7.

No

Go to the next step.

6

INSPECT BRAKE FLUID LEVEL SENSOR

Yes

Go to the next step.

No

Replace the brake fluid level sensor, then go to the next step.

(See MASTER CYLINDER REMOVAL/INSTALLATION.)

7

VERIFY THAT REPAIRS HAVE BEEN COMPLETED

Yes

Repeat the inspection from Step 1.

Go to the next step.

No

Go to the next step.

8

VERIFY IF OTHER DTCs DISPLAYED

  • Are any other DTCs displayed?

Yes

Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.

(See DTC TABLE [BCM].)

No

DTC troubleshooting completed.

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