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 POROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
1		No	Go to the next step.
2	INSPECT COOLING FAN RELAY NO. 1 Switch the ignition off. Remove the cooling fan relay No. 1. Inspect the cooling fan relay No. 1. (See RELAY INSPECTION .) Is there any malfunction?	Yes	Replace the cooling fan relay No. 1, then go to Step 8.
2		No	Go to the next step.
3	INSPECT COOLING FAN RELAY NO. 1 POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT Cooling fan relay No. 1 is removed. Switch the ignition ON (engine off). Measure the voltage at the cooling fan relay No. 1 terminal A (wiring harness-side). Is the voltage B+?	Yes	Go to the next step.
3		No	Inspect the ENGINE3 15 A fuse. If the fuse is blown: Refer to the wiring diagram and verify whether or not there is a common connector between ENGINE3 15 A fuse and cooling fan relay No. 1 terminal A. 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 a short to ground. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has a short to ground. Replace the fuse. If the fuse is damaged: Replace the fuse. If the fuse is normal: Refer to the wiring diagram and verify whether or not there is a common connector between main relay terminal D and cooling fan relay No. 1 terminal A. 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.
4	INSPECT COOLING FAN RELAY NO. 1 SIGNAL CIRCUIT FOR SHORT TO GROUND Cooling fan relay No. 1 is removed. Switch the ignition off. Inspect for continuity between cooling fan relay No. 1 terminal E (wiring harness-side) and body ground. Is there continuity?	Yes	If the short to ground circuit could be detected in the wiring harness: Refer to the wiring diagram and verify whether or not there is a common connector between cooling fan relay No. 1 terminal E and PCM terminal 2AU. 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 a short to ground. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has a short to ground. If the short to ground circuit could not be detected in the wiring harness: Replace the PCM (short to ground in the PCM internal circuit). (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Go to Step 8.
4		No	Go to the next step.
5	INSPECT PCM CONNECTOR CONDITION Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the connector and/or terminals, then go to Step 8.
5		No	Go to the next step.
6	INSPECT COOLING FAN RELAY NO. 1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY Cooling fan relay No. 1 is removed. Verify that the PCM connector is disconnected. Switch the ignition ON (engine off). NOTE: Another DTC may be stored by the PCM detecting an open circuit. Measure the voltage at the cooling fan relay No. 1 terminal E (wiring harness-side). Is the voltage 0 V?	Yes	Go to the next step.
6		No	Refer to the wiring diagram and verify whether or not there is a common connector between cooling fan relay No. 1 terminal E and PCM terminal 2AU. 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 a short to power supply. Repair or replace the malfunctioning part. If there is no common connector: Repair or replace the wiring harness which has a short to power supply. Go to Step 8.
7	INSPECT COOLING FAN RELAY NO. 1 SIGNAL CIRCUIT FOR OPEN CIRCUIT Cooling fan relay No. 1 is removed. Verify that the PCM connector is disconnected. Switch the ignition off. Inspect for continuity between cooling fan relay No. 1 terminal E (wiring harness-side) and PCM terminal 2AU (wiring harness-side). Is there continuity?	Yes	Go to the next step.
7		No	Refer to the wiring diagram and verify whether or not there is a common connector between cooling fan relay No. 1 terminal E and PCM terminal 2AU. 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 the next step.
8	VERIFY DTC TROUBLESHOOTING COMPLETED Always reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .) Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .) Is the same DTC present?	Yes	Repeat the inspection from Step 1. If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Go to the next step.
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
9		No	DTC troubleshooting completed.