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Home >> Mazda >> 2017 >> CX-5 Grand Select, FWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> On-Board Diagnostic - Connectivity Master Unit >> DTC B1238:01 [Connectivity Master Unit] >> Diagnostic Procedure

Diagnostic Procedure

DTC B1238:01 DIAGNOSTIC PROCEDURE

Step Inspection Action
1 DETERMINE MALFUNCTIONING SPEAKER Yes Go to Step 27.
No No audio produced from front door speaker (LH) and tweeter (LH)
  • Go to the next step.

    No audio produced from front door speaker (RH) and tweeter (RH)

  • Go to Step 9.

    No sound produced from rear door speaker (LH)

  • Go to Step 16.

    No audio produced from rear door speaker (RH)

  • Go to Step 21.

    No audio produced from all speakers.

  • Go to Step 26.
2 INSPECT TUNER AND AMP UNIT (TAU) CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the tuner and amp unit (TAU) 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 27.
3 INSPECT FRONT DOOR SPEAKER (LH) CONNECTOR CONDITION
  • Disconnect the front door speaker (LH) 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 27.
4 INSPECT TWEETER (LH) CONNECTOR CONDITION
  • Disconnect the tweeter (LH) 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 27.
5 INSPECT FRONT DOOR SPEAKER (LH) CIRCUIT FOR SHORT TO GROUND
  • Verify that the following connectors are disconnected.
    • Tuner and amp unit (TAU)
    • Front door speaker (LH)
      • Tweeter (LH)
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground.
    • Front door speaker (LH) terminal B
      • Front door speaker (LH) terminal C
  • Is there continuity?
Yes Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2A and front door speaker (LH) terminal B
  • Tuner and amp unit (TAU) terminal 2C and front door speaker (LH) terminal C
  • Tuner and amp unit (TAU) terminal 2A and tweeter (LH) terminal B
  • Tuner and amp unit (TAU) terminal 2C and tweeter (LH) terminal A

    If there is a common connector:

  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to ground.

Go to Step 27.
No Go to the next step.
6 INSPECT FRONT DOOR SPEAKER (LH) CIRCUIT FOR SHORT TO POWER SUPPLY
  • Verify that the following connectors are disconnected.
    • Tuner and amp unit (TAU)
    • Front door speaker (LH)
      • Tweeter (LH)
  • Reconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side).
    • Front door speaker (LH) terminal B
      • Front door speaker (LH) terminal C
  • Is the voltage 0 V?
Yes Go to the next step.
No Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2A and front door speaker (LH) terminal B
  • Tuner and amp unit (TAU) terminal 2C and front door speaker (LH) terminal C
  • Tuner and amp unit (TAU) terminal 2A and tweeter (LH) terminal B
  • Tuner and amp unit (TAU) terminal 2C and tweeter (LH) terminal A If there is a common connector:
  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 27.
7 INSPECT FRONT DOOR SPEAKER (LH) Yes Go to the next step.
No Replace the front door speaker (LH), then go to Step 27.
(See FRONT DOOR SPEAKER REMOVAL/INSTALLATION .)
8 INSPECT TWEETER (LH) Yes Go to Step 27.
No Replace the tweeter (LH), then go to Step 27.
(See TWEETER REMOVAL/INSTALLATION .)
9 INSPECT TUNER AND AMP UNIT (TAU) CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the tuner and amp unit (TAU) 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 27.
10 INSPECT FRONT DOOR SPEAKER (RH) CONNECTOR CONDITION
  • Disconnect the front door speaker (RH) 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 27.
11 INSPECT TWEETER (RH) CONNECTOR CONDITION
  • Disconnect the tweeter (RH) 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 27.
12 INSPECT FRONT DOOR SPEAKER (RH) CIRCUIT FOR SHORT TO GROUND
  • Verify that the following connectors are disconnected.
    • Tuner and amp unit (TAU)
    • Front door speaker (RH)
      • Tweeter (RH)
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground.
    • Front door speaker (RH) terminal C
      • Front door speaker (RH) terminal B
  • Is there continuity?
Yes Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2D and front door speaker (RH) terminal C
  • Tuner and amp unit (TAU) terminal 2F and front door speaker (RH) terminal B
  • Tuner and amp unit (TAU) terminal 2D and tweeter (RH) terminal B
  • Tuner and amp unit (TAU) terminal 2F and tweeter (RH) terminal A

    If there is a common connector:

  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to ground.

Go to Step 27.
No Go to the next step.
13 INSPECT FRONT DOOR SPEAKER (RH) CIRCUIT FOR SHORT TO POWER SUPPLY
  • Verify that the following connectors are disconnected.
    • Tuner and amp unit (TAU)
    • Front door speaker (RH)
      • Tweeter (RH)
  • Reconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side).
    • Front door speaker (RH) terminal C
      • Front door speaker (RH) terminal B
  • Is the voltage 0 V?
Yes Go to the next step.
No Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2D and front door speaker (RH) terminal C
  • Tuner and amp unit (TAU) terminal 2F and front door speaker (RH) terminal B
  • Tuner and amp unit (TAU) terminal 2D and tweeter (RH) terminal B
  • Tuner and amp unit (TAU) terminal 2F and tweeter (RH) terminal A

    If there is a common connector:

  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 27.
14 INSPECT FRONT DOOR SPEAKER (RH) Yes Go to the next step.
No Replace the front door speaker (RH), then go to Step 27.
(See FRONT DOOR SPEAKER REMOVAL/INSTALLATION .)
15 INSPECT TWEETER (RH) Yes Go to Step 27.
No Replace the tweeter (RH), then go to Step 27.
(See TWEETER REMOVAL/INSTALLATION .)
16 INSPECT TUNER AND AMP UNIT (TAU) CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the tuner and amp unit (TAU) 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 27.
17 INSPECT REAR DOOR SPEAKER (LH) CONNECTOR CONDITION
  • Disconnect the rear door speaker (LH) 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 27.
18 INSPECT REAR DOOR SPEAKER (LH) CIRCUIT FOR SHORT TO GROUND
  • Verify that the rear door speaker (LH) and tuner and amp unit (TAU) connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground.
    • Rear door speaker (LH) terminal C
      • Rear door speaker (LH) terminal B
  • Is there continuity?
Yes Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2S and rear door speaker (LH) terminal C
  • Tuner and amp unit (TAU) terminal 2U and rear door speaker (LH) terminal B If there is a common connector:
  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to ground.

Go to Step 27.
No Go to the next step.
19 INSPECT REAR DOOR SPEAKER (LH) CIRCUIT FOR SHORT TO POWER SUPPLY
  • Verify that the rear door speaker (LH) and tuner and amp unit (TAU) connectors are disconnected.
  • Reconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side).
    • Rear door speaker (LH) terminal C
      • Rear door speaker (LH) terminal B
  • Is the voltage 0 V?
Yes Go to the next step.
No Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2S and rear door speaker (LH) terminal C
  • Tuner and amp unit (TAU) terminal 2U and rear door speaker (LH) terminal B If there is a common connector:
  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 27.
20 INSPECT REAR DOOR SPEAKER (LH) Yes Go to Step 27.
No Replace the rear door speaker (LH), then go to Step 27.
(See REAR DOOR SPEAKER REMOVAL/INSTALLATION .)
21 INSPECT TUNER AND AMP UNIT (TAU) CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the tuner and amp unit (TAU) 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 27.
22 INSPECT REAR DOOR SPEAKER (RH) CONNECTOR CONDITION
  • Disconnect the rear door speaker (RH) 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 27.
23 INSPECT REAR DOOR SPEAKER (RH) CIRCUIT FOR SHORT TO GROUND
  • Verify that the rear door speaker (RH) and tuner and amp unit (TAU) connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground.
    • Rear door speaker (RH) terminal C
      • Rear door speaker (RH) terminal B
  • Is there continuity?
Yes Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2V and rear door speaker (RH) terminal C
  • Tuner and amp unit (TAU) terminal 2X and rear door speaker (RH) terminal B If there is a common connector:
  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to ground.

Go to Step 27.
No Go to the next step.
24 INSPECT REAR DOOR SPEAKER (RH) CIRCUIT FOR SHORT TO POWER SUPPLY
  • Verify that the rear door speaker (RH) and tuner and amp unit (TAU) connectors are disconnected.
  • Reconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side).
    • Rear door speaker (RH) terminal C
      • Rear door speaker (RH) terminal B
  • Is the voltage 0 V?
Yes Go to the next step.
No Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2V and rear door speaker (RH) terminal C
  • Tuner and amp unit (TAU) terminal 2X and rear door speaker (RH) terminal B

    If there is a common connector:

  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 27.
25 INSPECT REAR DOOR SPEAKER (RH) Yes Go to Step 27.
No Replace the rear door speaker (RH), then go to Step 27.
(See REAR DOOR SPEAKER REMOVAL/INSTALLATION .)
26 INSPECT TUNER AND AMP UNIT (TAU) CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the tuner and amp unit (TAU) 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 the next step.
27 VERIFY THAT REPAIRS HAVE BEEN COMPLETED Yes Repeat the inspection from Step 1.
Go to the next step.
No Go to the next step.
28 VERIFY IF OTHER DTCs DISPLAYED
  • Are any other DTCs displayed?
Yes Repair the malfunctioning location according to the applicable DTC troubleshooting.
(See DTC TABLE [CONNECTIVITY MASTER UNIT] .)
No DTC troubleshooting completed.


DTC B1238:01 DIAGNOSTIC PROCEDURE

Step Inspection Action
1 INSPECT AUDIO AMPLIFIER CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Disconnect the audio amplifier 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 6.
2 INSPECT TUNER AND AMP UNIT (TAU) CONNECTOR CONDITION
  • Disconnect the tuner and amp unit (TAU) 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 6.
3 INSPECT AUDIO AMPLIFIER CIRCUIT FOR SHORT TO GROUND
  • Verify that the audio amplifier and tuner and amp unit (TAU) connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground.
    • Audio amplifier terminal 1O
    • Audio amplifier terminal 1P
    • Audio amplifier terminal 1M
    • Audio amplifier terminal 1N
    • Audio amplifier terminal 2F
    • Audio amplifier terminal 1K
    • Audio amplifier terminal 2H
    • Audio amplifier terminal 1L
    • Audio amplifier terminal 1I
      • Audio amplifier terminal 1J
  • Is there continuity?
Yes Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2A and audio amplifier terminal 1O
  • Tuner and amp unit (TAU) terminal 2C and audio amplifier terminal 1P
  • Tuner and amp unit (TAU) terminal 2D and audio amplifier terminal 1M
  • Tuner and amp unit (TAU) terminal 2F and audio amplifier terminal 1N
  • Tuner and amp unit (TAU) terminal 2J and audio amplifier terminal 2F
  • Tuner and amp unit (TAU) terminal 2S and audio amplifier terminal 1K
  • Tuner and amp unit (TAU) terminal 2T and audio amplifier terminal 2H
  • Tuner and amp unit (TAU) terminal 2U and audio amplifier terminal 1L
  • Tuner and amp unit (TAU) terminal 2V and audio amplifier terminal 1I
  • Tuner and amp unit (TAU) terminal 2X and audio amplifier terminal 1J

    If there is a common connector:

  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to ground.

Go to Step 6.
No Go to the next step.
4 INSPECT AUDIO AMPLIFIER CIRCUIT FOR SHORT TO POWER SUPPLY
  • Verify that the audio amplifier and tuner and amp unit (TAU) connectors are disconnected.
  • Reconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side).
    • Audio amplifier terminal 1O
    • Audio amplifier terminal 1P
    • Audio amplifier terminal 1M
    • Audio amplifier terminal 1N
    • Audio amplifier terminal 2F
    • Audio amplifier terminal 1K
    • Audio amplifier terminal 2H
    • Audio amplifier terminal 1L
    • Audio amplifier terminal 1I
      • Audio amplifier terminal 1J
  • Is the voltage 0 V?
Yes Go to the next step.
No Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Tuner and amp unit (TAU) terminal 2A and audio amplifier terminal 1O
  • Tuner and amp unit (TAU) terminal 2C and audio amplifier terminal 1P
  • Tuner and amp unit (TAU) terminal 2D and audio amplifier terminal 1M
  • Tuner and amp unit (TAU) terminal 2F and audio amplifier terminal 1N
  • Tuner and amp unit (TAU) terminal 2J and audio amplifier terminal 2F
  • Tuner and amp unit (TAU) terminal 2S and audio amplifier terminal 1K
  • Tuner and amp unit (TAU) terminal 2T and audio amplifier terminal 2H
  • Tuner and amp unit (TAU) terminal 2U and audio amplifier terminal 1L
  • Tuner and amp unit (TAU) terminal 2V and audio amplifier terminal 1I
  • Tuner and amp unit (TAU) terminal 2X and audio amplifier terminal 1J

    If there is a common connector:

  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to power supply to determine the malfunctioning location.
  • Repair or replace the malfunctioning location.

    If there is no common connector:

  • Repair or replace the wiring harness which is shorted to the power supply.

Go to Step 6.
5 PERFORM DTC INSPECTION AND VERIFY IF MALFUNCTIONING PART IS AUDIO AMPLIFIER Yes Replace the audio amplifier, then go to the next step.
(See AUDIO AMPLIFIER REMOVAL/INSTALLATION .)
No Go to Step 7.
6 VERIFY THAT REPAIRS HAVE BEEN COMPLETED Yes Repeat the inspection from Step 1.
Go to the next step.
No Go to the next step.
7 VERIFY IF OTHER DTCs DISPLAYED
  • Are any other DTCs displayed?
Yes Repair the malfunctioning location according to the applicable DTC troubleshooting.
(See DTC TABLE [CONNECTIVITY MASTER UNIT] .)
No DTC troubleshooting completed.