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Home >> Mazda >> 2017 >> CX-5 Grand Select, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 67 (On-Board Diagnostic - Connectivity Master Unit) >> DTC B108E-87: Center Display Circuit Malfunction >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.
Step Inspection Action
1 INSPECT CENTER DISPLAY CONNECTOR CONDITION  Yes Go to the next step.
No Repair or replace the connector, then go to Step 7.
2 INSPECT CONNECTIVITY MASTER UNIT (CMU) CONNECTOR CONDITION 
  • Disconnect the connectivity master unit (CMU) 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.
3 INSPECT CENTER DISPLAY CIRCUIT FOR SHORT TO GROUND 
  • Verify that the center display and connectivity master unit (CMU) connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground.
    • Center display terminal 2B
    • Center display terminal 2D
  • Is there continuity?
Yes Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Connectivity master unit (CMU) terminal 3B and center display terminal 2B
  • Connectivity master unit (CMU) terminal 3D and center display terminal 2D

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 7.
No Go to the next step.
4 INSPECT CENTER DISPLAY CIRCUIT FOR SHORT TO POWER SUPPLY 
  • Verify that the center display and connectivity master unit (CMU) connectors are disconnected.
  • Connect the negative battery cable.

    (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)

  • Switch the ignition ON (engine off or on).
  • Measure the voltage at the following terminals (wiring harness-side).
    • Center display terminal 2B
    • Center display terminal 2D
  • 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.
  • Connectivity master unit (CMU) terminal 3B and center display terminal 2B
  • Connectivity master unit (CMU) terminal 3D and center display terminal 2D

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 7.
5 INSPECT CENTER DISPLAY CIRCUIT FOR OPEN CIRCUIT 
  • Switch the ignition off.
  • Disconnect the negative battery cable.

    (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)

  • Verify that the center display and connectivity master unit (CMU) connectors are disconnected.
  • Inspect the wiring harness for continuity between the following terminals (wiring harness-side).
    • Connectivity master unit (CMU) terminal 3B and center display terminal 2B
    • Connectivity master unit (CMU) terminal 3D and center display terminal 2D
  • Is there continuity?
Yes Go to the next step.
No Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Connectivity master unit (CMU) terminal 3B and center display terminal 2B
  • Connectivity master unit (CMU) terminal 3D and center display terminal 2D

If there is a common connector: 

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

If there is no common connector: 

  • Repair or replace the wiring harness which has an open circuit.

Go to Step 7.
6 VERIFY IF MALFUNCTIONING LOCATION IS CENTER DISPLAY DEPENDING ON REPEATABILITY  Yes Replace the center display, then go to the next step.
(See CENTER DISPLAY REMOVAL/INSTALLATION .)
No Go to Step 8.
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 [CONNECTIVITY MASTER UNIT] .)
No DTC troubleshooting completed.