Troubleshooting Diagnostic Procedure

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.

Intention of troubleshooting procedure

Step 1-2
- Perform an inspection of the HO2S and PCM-related connectors.
Step 3
- Perform an inspection of the short to power supply in wiring harness between HO2S and PCM.
Step 4
- Perform a unit inspection of the HO2S.
Step 5-6
- Verify that the primary malfunction is resolved and there are no other malfunctions.

STEP	INSPECTION	RESULTS	ACTION
1	PURPOSE: INSPECT HO2S CONNECTOR CONDITION Switch the ignition off. Disconnect the HO2S 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 5.
1		No	Go to the next step.
2	PURPOSE: 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 5.
2		No	Go to the next step.
3	PURPOSE: INSPECT HO2S CIRCUIT FOR SHORT TO POWER SUPPLY Verify that the HO2S and PCM connectors are disconnected. Switch the ignition ON (engine off). Measure the voltage at the following terminals (wiring harness-side): HO2S terminal A HO2S terminal B Is the voltage 0 V ?	Yes	Go to the next step.
3		No	Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals: HO2S terminal A-PCM terminal 2AI HO2S terminal B-PCM terminal 2AG 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 5.
4	PURPOSE: DETERMINE INTEGRITY OF HO2S Reconnect all disconnected connectors. Inspect the HO2S. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Is there any malfunction?	Yes	Replace the HO2S, then go to the next step. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
4		No	Go to the next step.
5	PURPOSE: VERIFICATION OF VEHICLE REPAIR COMPLETION Always reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. (See CLEARING DTC [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .) Is the PENDING CODE for this 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.
5		No	Go to the next step.
6	PURPOSE: VERIFY IF THERE IS ANY OTHER MALFUNCTION Is any other DTC or pending code stored?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
6		No	DTC troubleshooting completed.