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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 U0184-00: Communication Error With Tuner And Amp Unit U0187-00: Communication Error With Cd Player >> 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 FOR POWER SUPPLY-RELATED MALFUNCTION  Yes
NOTE:
  • It may be affected by power supply-related or DC-DC converter malfunction.
Repair the malfunctioning location according to the applicable DTC troubleshooting.(See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)(See DTC TABLE [CONNECTIVITY MASTER UNIT] .)
No Go to the next step.
2 INSPECT FOR SHORT TO POWER SUPPLY IN CAN_H SIDE CIRCUIT OF LOCAL-CAN 
  • Measure the voltage between connectivity master unit (CMU) terminal 2I (LOCAL-CAN CAN_H side) and body ground.
  • Is the voltage B+  ?
 Yes A short to power supply in CAN_H side circuit of LOCAL-CAN has occurred.
  • Go to Step 6.
No Go to the next step.
3 INSPECT FOR SHORT TO GROUND IN CAN_L SIDE CIRCUIT OF LOCAL-CAN 
  • Measure the voltage between connectivity master unit (CMU) terminal 2J (LOCAL-CAN CAN_L side) and body ground.
  • Is the voltage 0 V  ?
 Yes A short to ground in CAN_L side circuit of LOCAL-CAN has occurred.
  • Go to Step 7.
No Go to the next step.
4 INSPECT BETWEEN LOCAL-CAN_L AND LOCAL-CAN_H SIDE CIRCUITS FOR SHORT BETWEEN CIRCUITS  Yes Go to the next step. (LOCAL-CAN is normal)
No If the resistance is 0 ohm: 
  • A short between circuits has occurred in LOCAL-CAN.
  • Go to Step 8.

If the resistance is 120 ohms: 

  • An open circuit in the LOCAL-CAN has occurred.
    • Go to Step 9.
5 DETERMINE MALFUNCTIONING LOCATION 
  • U0184:00
  • U0187:00
 Yes If U0184:00 is only displayed: 
  • Go to Step 10.

If U0187:00 is only displayed: 

  • Go to Step 11.

If all DTCs are displayed: 
No Go to Step 15.
6 INSPECT WIRING HARNESS FOR SHORT TO POWER SUPPLY  Yes Go to Step 13.
No Refer to the wiring diagram and verify if there is a common connector between the following terminals.
  • Connectivity master unit (CMU) terminal 2I-Tuner and amp unit (TAU) terminal 2O
  • Connectivity master unit (CMU) terminal 2I-CD player terminal G

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 14.
7 INSPECT WIRING HARNESS FOR SHORT TO GROUND 
  • Switch the ignition off.
  • Disconnect the negative battery cable.

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

  • Disconnect the following connectors:
    • Connectivity master unit (CMU)
    • Tuner and amp unit (TAU)
    • CD player
  • Inspect for continuity between the following terminals (vehicle wiring harness side) and body ground.
    • Connectivity master unit (CMU) terminal 2J
    • Tuner and amp unit (TAU) terminal 2Q
    • CD player terminal H
  • 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 2J-Tuner and amp unit (TAU) terminal 2Q
  • Connectivity master unit (CMU) terminal 2J-CD player terminal H

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 14.
No Go to Step 13.
8 INSPECT WIRING HARNESS FOR SHORT BETWEEN CIRCUITS 
  • Switch the ignition off.
  • Disconnect the negative battery cable.

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

  • Disconnect the following connectors:
    • Connectivity master unit (CMU)
    • Tuner and amp unit (TAU)
    • CD player
  • Inspect between the following terminals (vehicle wiring harness side) for continuity.
    • Connectivity master unit (CMU) terminals 2I and 2J
    • Tuner and amp unit (TAU) terminals 2O and 2Q
    • CD player terminals G and H
  • 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 2I-Tuner and amp unit (TAU) terminal 2O
  • Connectivity master unit (CMU) terminal 2J-Tuner and amp unit (TAU) terminal 2Q
  • Connectivity master unit (CMU) terminal 2I-CD player terminal G
  • Connectivity master unit (CMU) terminal 2J-CD player terminal H

If there is a common connector: 

  • Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short between circuits 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 shorted between circuits.

Go to Step 14.
No Go to Step 13.
9 INSPECT WIRING HARNESS 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] .)

  • Disconnect the following connectors:
    • Connectivity master unit (CMU)
    • Tuner and amp unit (TAU)
    • CD player
    • Connector C-37
  • Inspect the wiring harness for continuity between the following terminals (vehicle wiring harness side).
    • Connectivity master unit (CMU) terminal 2I-Connector C-37
    • Connectivity master unit (CMU) terminal 2J-Connector C-37
    • Tuner and amp unit (TAU) terminal 2O-Connector C-37
    • Tuner and amp unit (TAU) terminal 2Q-Connector C-37
    • CD player terminal G-Connector C-37
    • CD player terminal H-Connector C-37
  • 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 2I-Connector C-37
  • Connectivity master unit (CMU) terminal 2J-Connector C-37
  • Tuner and amp unit (TAU) terminal 2O-Connector C-37
  • Tuner and amp unit (TAU) terminal 2Q-Connector C-37
  • CD player terminal G-Connector C-37
  • CD player terminal H-Connector C-37

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 14.
No Go to Step 13.
10 INSPECT TUNER AND AMP UNIT (TAU) RELATED-WIRING HARNESS FOR OPEN CIRCUIT  Yes Replace the tuner and amp unit (TAU), then go to Step 14.
(See TUNER AND AMP UNIT (TAU) REMOVAL/INSTALLATION .)
No Repair or replace the wiring harness which has an open circuit, then go to Step 14.
11 INSPECT CD PLAYER RELATED-WIRING HARNESS FOR OPEN CIRCUIT  Yes Go to the next step.
No Repair or replace the wiring harness which has an open circuit, then go to Step 14.
12 VERIFY CD PLAYER POWER SUPPLY VOLTAGE  Yes Replace the CD player, then go to Step 14.
(See CD PLAYER REMOVAL/INSTALLATION .)
No Inspect the INTERIOR 15 A fuse, ROOM 25 A fuse and MAIN 200 A fuse.
  • If the fuse is blown:
    • Refer to the wiring diagram and verify if there is a common connector between MAIN 200 A fuse and CD player terminal Z.

      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.
      • Replace the fuse.
  • If the fuse is damaged:
    • Replace the fuse.
  • If the fuse is normal:
    • Refer to the wiring diagram and verify if there is a common connector between battery positive terminal and CD player terminal Z.

      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 14.
13 PERFORM DTC INSPECTION AND DETERMINE MALFUNCTIONING LOCATION  Yes If U0184:00 is only displayed: 

If U0187:00 is only displayed: 

If all DTCs are displayed: 
No Go to Step 15.
14 VERIFY THAT REPAIRS HAVE BEEN COMPLETED  Yes Repeat the inspection from Step 1.
Go to the next step.
No Go to the next step.
15 VERIFY OTHER DTCs 
  • 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.
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