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 U0198:00 (CONNECTIVITY MASTER UNIT) 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	INSPECT TELEMATICS COMMUNICATION UNIT FOR MALFUNCTION Perform the DTC inspection for the telematics communication unit. (Refer to the [DTC INSPECTION] in the appropriate service information) Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (Refer to the [DTC TABLE [TELEMATICS COMMUNICATION UNIT]] in the appropriate service information)
2		No	Go to the next step.
3	VERIFY TELEMATICS COMMUNICATION UNIT POWER SUPPLY VOLTAGE Measure the voltage at telematics communication unit terminal 1AF (vehicle wiring harness side). Is voltage supplied?	Yes	Go to Step 7.
3		No	Go to the next step.
4	INSPECT TELEMATICS COMMUNICATION UNIT 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 TELEMATICS COMMUNICATION UNIT POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT Inspect the power supply circuit for a short to ground and open circuit. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is the circuit normal?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning location and perform the repair completion verification.
6	INSPECT TELEMATICS COMMUNICATION UNIT 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 Step 8.
6		No	Repair or replace the malfunctioning location and perform the repair completion verification.
7	INSPECT TELEMATICS COMMUNICATION UNIT 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.
7		No	Repair or replace the malfunctioning location and perform the repair completion verification.
8	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.
8		No	Repair or replace the malfunctioning location and perform the repair completion verification.
9	INSPECT CIRCUIT BETWEEN CONNECTIVITY MASTER UNIT (CMU) AND TELEMATICS COMMUNICATION UNIT 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.
9		No	Repair or replace the malfunctioning location and perform the repair completion verification.
10	INSPECT CIRCUIT BETWEEN CONNECTIVITY MASTER UNIT (CMU) AND TELEMATICS COMMUNICATION UNIT 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.
10		No	Repair or replace the malfunctioning location and perform the repair completion verification.
11	INSPECT CIRCUIT BETWEEN CONNECTIVITY MASTER UNIT (CMU) AND TELEMATICS COMMUNICATION UNIT 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	INSPECT SHIELDING CIRCUIT BETWEEN CONNECTIVITY MASTER UNIT (CMU) AND TELEMATICS COMMUNICATION UNIT Inspect the applicable circuit for continuity with the body ground. (Refer to the [CIRCUIT INSPECTION] in the appropriate service information) Is there continuity?	Yes	Go to the next step.
12		No	Repair or replace the malfunctioning location and perform the repair completion verification.
13	DETERMINE MALFUNCTIONING LOCATION 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) Are other DTCs displayed that are the same as this DTC?	Yes	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)
13		No	Replace the telematics communication unit and perform the repair completion verification. (Refer to the [TELEMATICS COMMUNICATION UNIT REMOVAL/INSTALLATION] in the appropriate service information)
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.