Troubleshooting Diagnostic Procedure

U0186-02: (CMU) TROUBLESHOOTING DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	PURPOSE: VERIFY AUDIO AMPLIFIER OPERATION Output audio in the cabin using the audio amplifier. (Such as radio, navigation) Is audio output from the vehicle speakers?	Yes	Go to repair completion verification 1.
1		No	Go to the next step.
2	PURPOSE: VERIFY SUPPLY VOLTAGE TO AUDIO AMPLIFIER Measure the voltage at audio amplifier terminal 1A (wiring harness-side). Is the voltage B+?	Yes	Go to the next step.
2		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
3	PURPOSE: INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN AUDIO AMPLIFIER AND BODY GROUND FOR MALFUNCTION Inspect the applicable circuit. (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
4	PURPOSE: INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN BATTERY/LEAD-ACID BATTERY (WITH Mazda M Hybrid)/DC-DC CONVERTER (WITHOUT Mazda M Hybrid) AND AUDIO AMPLIFIER FOR MALFUNCTION Inspect the applicable circuit. (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
5	PURPOSE: VERIFY MOST WAKE UP CIRCUIT VOLTAGE Measure the voltage at audio amplifier terminal 2K (wiring harness-side). (With Bose®) Measure the voltage at audio amplifier terminal 1N (wiring harness-side). (Without Bose®) Is the voltage B+?	Yes	Go to Step 10.
5		No	Go to the next step.
6	PURPOSE: VERIFY MOST WAKE UP CIRCUIT VOLTAGE NOTE: Measure while the emergency call system is not operating. Measure the voltage at emergency call unit/telematics communication unit 1Z (wiring harness-side). Is the voltage B+?	Yes	Go to the next step.
6		No	Go to Step 8.
7	PURPOSE: INSPECT EMERGENCY CALL UNIT/TELEMATICS COMMUNICATION UNIT FOR MALFUNCTION Perform the DTC inspection for the emergency call unit/telematics communication unit. (See DTC INSPECTION .) Are any DTCs displayed?	Yes	Repair or replace the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [TCU] .)
7		No	Go to the next step.
8	PURPOSE: INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN AUDIO AMPLIFIER AND EMERGENCY CALL UNIT/TELEMATICS COMMUNICATION UNIT FOR MALFUNCTION Inspect the applicable circuit. (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
8		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
9	PURPOSE: INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN EMERGENCY CALL UNIT/TELEMATICS COMMUNICATION UNIT AND CONNECTIVITY MASTER UNIT (CMU) FOR MALFUNCTION Inspect the applicable circuit. (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
9		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
10	PURPOSE: INSPECT WIRING HARNESS (INCLUDING CONNECTOR/TERMINAL) BETWEEN AUDIO AMPLIFIER AND CONNECTIVITY MASTER UNIT (CMU) FOR MALFUNCTION Inspect the applicable circuit. (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Is the circuit normal?	Yes	Go to the next step.
10		No	Repair or replace the malfunctioning location and perform the repair completion verification 1.
11	PURPOSE: DETERMINE MALFUNCTIONING LOCATION Replace the audio amplifier. (Refer to AUDIO AMPLIFIER REMOVAL/INSTALLATION in service information.) Output audio in the cabin using the audio amplifier. (Such as radio, navigation) Is audio output from the vehicle speakers?	Yes	Go to repair completion verification 1.
11		No	Replace the connectivity master unit (CMU), and perform the repair completion verification 1. (Refer to CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION in service information.)
Repair completion verification 1	PURPOSE: VERIFY THAT VEHICLE IS REPAIRED Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Replicate the vehicle conditions at the time the DTC was detected using the following procedure. Implement the repeatability verification procedure. (See REPEATABILITY VERIFICATION PROCEDURE .) Perform the DTC inspection for the connectivity master unit (CMU). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See MALFUNCTION DIAGNOSIS FLOW [CONTROLLER AREA NETWORK (CAN)] .) 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 CONNECTIVITY MASTER UNIT (CMU) REMOVAL/INSTALLATION in service information.)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	PURPOSE: VERIFY IF OTHER DTCs DISPLAYED Perform the DTC inspection. (See DTC INSPECTION .) Are any other DTCs displayed?	Yes	Repair or replace the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.