Diagnostic Procedure

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

DIAGNOSTIC PROCEDURE

Step	Inspection		Action
1	INSPECT AUDIO AMPLIFIER CONNECTOR CONDITION 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 audio amplifier 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.
1		No	Repair or replace the connector, then go to Step 6.
2	INSPECT TUNER AND AMP UNIT CONNECTOR CONDITION Disconnect the tuner and amp unit 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.
2		No	Repair or replace the connector, then go to Step 6.
3	INSPECT AUDIO AMPLIFIER CIRCUIT FOR SHORT TO GROUND Verify that the audio amplifier and tuner and amp unit connectors are disconnected. Inspect for continuity between the following terminals (wiring harness-side) and body ground. Audio amplifier terminal 1O Audio amplifier terminal 1P Audio amplifier terminal 1M Audio amplifier terminal 1N Audio amplifier terminal 2F Audio amplifier terminal 1K Audio amplifier terminal 2H Audio amplifier terminal 1L Audio amplifier terminal 1I Audio amplifier terminal 1J Is there continuity?	Yes	Refer to the wiring diagram and verify if there is a common connector between the following terminals. Tuner and amp unit terminal 2A and audio amplifier terminal 1O Tuner and amp unit terminal 2C and audio amplifier terminal 1P Tuner and amp unit terminal 2D and audio amplifier terminal 1M Tuner and amp unit terminal 2F and audio amplifier terminal 1N Tuner and amp unit terminal 2J and audio amplifier terminal 2F Tuner and amp unit terminal 2S and audio amplifier terminal 1K Tuner and amp unit terminal 2T and audio amplifier terminal 2H Tuner and amp unit terminal 2U and audio amplifier terminal 1L Tuner and amp unit terminal 2V and audio amplifier terminal 1I Tuner and amp unit terminal 2X and audio amplifier terminal 1J 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 6.
3		No	Go to the next step.
4	INSPECT AUDIO AMPLIFIER CIRCUIT FOR SHORT TO POWER SUPPLY Verify that the audio amplifier and tuner and amp unit connectors are disconnected. Reconnect 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). Audio amplifier terminal 1O Audio amplifier terminal 1P Audio amplifier terminal 1M Audio amplifier terminal 1N Audio amplifier terminal 2F Audio amplifier terminal 1K Audio amplifier terminal 2H Audio amplifier terminal 1L Audio amplifier terminal 1I Audio amplifier terminal 1J Is the voltage 0 V?	Yes	Go to the next step.
4		No	Refer to the wiring diagram and verify if there is a common connector between the following terminals. Tuner and amp unit terminal 2A and audio amplifier terminal 1O Tuner and amp unit terminal 2C and audio amplifier terminal 1P Tuner and amp unit terminal 2D and audio amplifier terminal 1M Tuner and amp unit terminal 2F and audio amplifier terminal 1N Tuner and amp unit terminal 2J and audio amplifier terminal 2F Tuner and amp unit terminal 2S and audio amplifier terminal 1K Tuner and amp unit terminal 2T and audio amplifier terminal 2H Tuner and amp unit terminal 2U and audio amplifier terminal 1L Tuner and amp unit terminal 2V and audio amplifier terminal 1I Tuner and amp unit terminal 2X and audio amplifier terminal 1J 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 6.
5	PERFORM DTC INSPECTION AND VERIFY IF MALFUNCTIONING PART IS AUDIO AMPLIFIER Always reconnect all disconnected connectors. Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Clear the DTC for the connectivity master unit using the M-MDS. (See CLEARING DTC [CONNECTIVITY MASTER UNIT] .) Switch the ignition ON (engine off or on) and wait for 7 s or more. Perform the DTC inspection for the connectivity master unit using the M-MDS. (See DTC INSPECTION [CONNECTIVITY MASTER UNIT] .) Is the same DTC displayed?	Yes	Replace the audio amplifier, then go to the next step. (See AUDIO AMPLIFIER REMOVAL/INSTALLATION .)
5		No	Go to Step 7.
6	VERIFY THAT REPAIRS HAVE BEEN COMPLETED Always reconnect all disconnected connectors. Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Clear the DTC for the connectivity master unit using the M-MDS. (See CLEARING DTC [CONNECTIVITY MASTER UNIT] .) Switch the ignition ON (engine off or on) and wait for 7 s or more. Perform the DTC inspection for the connectivity master unit using the M-MDS. (See DTC INSPECTION [CONNECTIVITY MASTER UNIT] .) Is the same DTC displayed?	Yes	Repeat the inspection from Step 1. If the malfunction recurs, replace the tuner and amp unit. (See TUNER AND AMP UNIT (TAU) REMOVAL/INSTALLATION .) Go to the next step.
6		No	Go to the next step.
7	VERIFY IF OTHER DTCs DISPLAYED Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [CONNECTIVITY MASTER UNIT] .)
7		No	DTC troubleshooting completed.