Diagnostic Procedure

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

DTC U2142:00 (CONNECTIVITY MASTER UNIT - US) DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	VERIFY REPEATABILITY Switch the ignition ON (engine off or on). Clear the DTC recorded in the memory. (Refer to the [CLEARING DTC] in the appropriate service information) Switch the ignition OFF, and then switch it ON (engine off or on) and wait for 30 s or more. Perform the DTC inspection for the connectivity master unit (CMU). (Refer to the [DTC INSPECTION] in the appropriate service information) Is the same Pending DTC present?	Yes	Go to the next step.
1		No	Go to repair completion verification 2.
2	VERIFY VOLTAGE SUPPLIED TO MICROPHONE Measure the voltage at microphone terminal B (vehicle wiring harness side). Is the voltage approx. 5.5 V?	Yes	Go to Step 9.
2		No	Go to the next step.
3	VERIFY VOLTAGE WHICH CONNECTIVITY MASTER UNIT (CMU) IS SUPPLYING Measure the voltage at connectivity master unit (CMU) terminal 1F. Is the voltage approx. 5.5 V?	Yes	Go to the next step.
3		No	Replace the connectivity master unit (CMU) and perform the repair completion verification. (Refer to the [CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION] in the appropriate service information)
4	INSPECT MICROPHONE CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (Refer to the [CONNECTOR INSPECTION] in the appropriate service information) Are the connector and terminal normal?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning location and perform the repair completion verification.
5	INSPECT CONNECTIVITY MASTER UNIT (CMU) CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (Refer to the [CONNECTOR INSPECTION] in the appropriate service information) Are the connector and terminal normal?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning location and perform the repair completion verification.
6	INSPECT MICROPHONE POWER SUPPLY CIRCUIT FOR SHORT TO GROUND Inspect the applicable circuit for a short to ground. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning location and perform the repair completion verification.
7	INSPECT MICROPHONE POWER SUPPLY CIRCUIT FOR SHORT TO POWER SUPPLY Inspect the applicable circuit for a short to power supply. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Go to the next step.
7		No	Repair or replace the malfunctioning location and perform the repair completion verification.
8	INSPECT MICROPHONE POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT Inspect the applicable circuit for an open circuit. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning location and perform the repair completion verification.
9	INSPECT MICROPHONE CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (Refer to the [CONNECTOR INSPECTION] in the appropriate service information) Are the connector and terminal normal?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning location and perform the repair completion verification.
10	INSPECT CONNECTIVITY MASTER UNIT (CMU) CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (Refer to the [CONNECTOR INSPECTION] in the appropriate service information) Are the connector and terminal normal?	Yes	Go to the next step.
10		No	Repair or replace the malfunctioning location and perform the repair completion verification.
11	INSPECT MICROPHONE GROUND CIRCUIT FOR OPEN CIRCUIT Inspect the applicable circuit for an open circuit. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Go to the next step.
11		No	Repair or replace the malfunctioning location and perform the repair completion verification.
12	VERIFY VOLTAGE SUPPLIED FROM MICROPHONE CONTROL CIRCUIT Measure the voltage at microphone terminal F (vehicle wiring harness side). Is the voltage approx. 5.43 V?	Yes	Replace the microphone and perform the repair completion verification (Refer to the [MICROPHONE REMOVAL/INSTALLATION] in the appropriate service information)
12		No	Go to the next step.
13	VERIFY VOLTAGE SUPPLIED AT CONTROL CIRCUIT CONTROLLED BY CONNECTIVITY MASTER UNIT (CMU) Measure the voltage at connectivity master unit (CMU) terminal 1G. Is the voltage approx. 5.43 V?	Yes	Go to the next step.
13		No	Replace the connectivity master unit (CMU) and perform the repair completion verification. (Refer to the [CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION] in the appropriate service information)
14	INSPECT MICROPHONE CONTROL CIRCUIT FOR SHORT TO GROUND Inspect the applicable circuit for a short to ground. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Go to the next step.
14		No	Repair or replace the malfunctioning location and perform the repair completion verification.
15	INSPECT MICROPHONE CONTROL CIRCUIT FOR SHORT TO POWER SUPPLY Inspect the applicable circuit for a short to power supply. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Go to the next step.
15		No	Repair or replace the malfunctioning location and perform the repair completion verification.
16	INSPECT MICROPHONE CONTROL CIRCUIT FOR OPEN CIRCUIT Inspect the applicable circuit for an open circuit. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Replace the microphone and perform the repair completion verification (Refer to the [MICROPHONE REMOVAL/INSTALLATION] in the appropriate service information)
16		No	Repair or replace the malfunctioning location and perform the repair completion verification.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (Refer to the [CLEARING DTC] in the appropriate service information) Perform the DTC inspection for the connectivity master unit (CMU). (Refer to the [DTC INSPECTION] in the appropriate service information) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (Refer to the [CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW] in the appropriate service information) If the CAN communication is normal, perform the diagnosis from Step 1. If the malfunction recurs, replace the connectivity master unit (CMU), then go to the next step. (Refer to the [CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION] in the appropriate service information)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs ARE DISPLAYED Perform the DTC inspection. (Refer to the [DTC INSPECTION] in the appropriate service information) Are other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.