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 STARTER INTERLOCK SWITCH 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 starter interlock switch 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 8.
2	INSPECT FOR OPEN CIRCUIT IN STARTER INTERLOCK SWITCH GROUND CIRCUIT Verify that the starter interlock switch connector is disconnected. Inspect for continuity between starter interlock switch terminal B (wiring harness-side) and body ground. Is there continuity?	Yes	Go to the next step.
2		No	Refer to the wiring diagram and verify whether or not there is a common connector between starter interlock switch terminal B and body ground. If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has an open circuit. Go to Step 8.
3	INSPECT STARTER INTERLOCK SWITCH Inspect the starter interlock switch. (See STARTER INTERLOCK SWITCH INSPECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Is the starter interlock switch normal?	Yes	Go to the next step.
3		No	Replace the starter interlock switch, then go to Step 8. (See STARTER INTERLOCK SWITCH REMOVAL/INSTALLATION [C66M-R] .)
4	INSPECT PCM CONNECTOR CONDITION Disconnect the PCM 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.
4		No	Repair or replace the connector, then go to Step 8.
5	INSPECT START STOP UNIT CONNECTOR CONDITION Disconnect the start stop 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.
5		No	Repair or replace the connector, then go to Step 8.
6	INSPECT FOR OPEN CIRCUIT IN STARTER INTERLOCK SWITCH CIRCUIT Verify that the start stop unit, PCM and starter interlock switch connectors are disconnected. Inspect for continuity between the following terminals (wiring harness-side): Starter interlock switch terminal A-PCM terminal 2BD Starter interlock switch terminal A-Start stop unit terminal 1F Is there continuity?	Yes	Go to the next step.
6		No	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: Starter interlock switch terminal A-PCM terminal 2BD Starter interlock switch terminal A-Start stop unit terminal 1F If there is a common connector: Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has an open circuit. Go to Step 8.
7	PERFORM DTC INSPECTION AND VERIFY PCM MALFUNCTION 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 start stop unit using the M-MDS. (See CLEARING DTC [START STOP UNIT] .) Switch the ignition ON (engine off or on). Perform the following work 5 times or more. Depress the clutch pedal for 1 s or more. Release the clutch pedal for 1 s or more. Retrieve the start stop unit DTCs using the M-MDS. (See DTC INSPECTION [START STOP UNIT] .) Is the same DTC displayed?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
7		No	Go to Step 9.
8	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 start stop unit using the M-MDS. (See CLEARING DTC [START STOP UNIT] .) Switch the ignition ON (engine off or on). Perform the following work 5 times or more. Depress the clutch pedal for 1 s or more. Release the clutch pedal for 1 s or more. Retrieve the start stop unit DTCs using the M-MDS. (See DTC INSPECTION [START STOP UNIT] .) Is the same DTC displayed?	Yes	Repeat the inspection from Step 1. If the malfunction recurs, replace the start stop unit. (See START STOP UNIT REMOVAL/INSTALLATION .) Go to the next step.
8		No	Go to the next step.
9	VERIFY IF OTHER DTCs DISPLAYED Are any other DTCs displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [START STOP UNIT] .)
9		No	DTC troubleshooting completed.