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HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 17 (ON-BOARD DIAGNOSTIC (ENGINE CONTROL SYSTEM L3) (2 OF 5))DTC P0131 [L3]DIAGNOSTIC PROCEDURE

2008 Mazda 6 s Sport, 4D Hatchback, Standard

Diagnostic Procedure

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Diagnostic Procedure

WARNING: This page is about a different variant/trim than selected.

DTC P0131 [L3] DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (HO2S related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	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.
2		No	Go to the next step.
3	VERIFY RELATED PENDING OR STORED DTC Turn the ignition switch off, then to the ON position (Engine off). Verify the pending code or stored DTCs using the M-MDS or equivalent. Is other DTC present?	Yes	Go to the appropriate DTC troubleshooting procedures. (See DTC TABLE [L3] ).
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA Is DTC P0131 on FREEZE FRAME DATA?	Yes	Go to the next step.
4		No	Go to troubleshooting procedures for DTC on FREEZE FRAME DATA. (See DTC TABLE [L3] ).
5	INSPECT FRONT HO2S CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the front HO2S connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 10.
5		No	Go to the next step.
6	INSPECT FRONT HO2S CIRCUIT FOR SHORT TO GROUND Turn the ignition switch off. Inspect for continuity between the following terminals and body ground: Front HO2S terminal A (wiring harness-side) and body ground Front HO2S terminal B (wiring harness-side) and body ground Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to ground, then go to Step 10.
6		No	Go to the next step.
7	INSPECT FRONT HO2S Inspect the front HO2S. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [L3] ). Is there any malfunction?	Yes	Replace the front HO2S, then go to Step 10. (See HO2S REMOVAL NOTE ).
7		No	Go to the next step.
8	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 10.
8		No	Go to the next step.
9	INSPECT FRONT HO2S CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch off. Inspect for continuity between the following circuits: Front HO2S terminal A (wiring harness-side) and PCM terminal 2AD (wiring harness-side) Front HO2S terminal B (wiring harness-side) and PCM terminal 2Z (wiring harness-side) Is there continuity?	Yes	Go to the next step.
9		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P0131 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS or equivalent. Perform the KOEO self-test (using M-MDS or equivalent) or the HO2S heater, HO2S, and TWC Repair Verification Drive Mode (not using M-MDS or equivalent). (See KOEO/KOER SELF TEST [L3] ). (See OBD-II DRIVE MODE [L3] ). Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L3] ).
10		No	Go to the next step.
11	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [L3] ). Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [L3] ).
11		No	DTC troubleshooting completed.

DTC P0131 [L3] DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (HO2S related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Information availability. Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING OR STORED DTC Turn the ignition switch off, then to the ON position (Engine off). Verify the pending code or stored DTCs using the M-MDS or equivalent. Are other DTCs present?	Yes	Go to the appropriate DTC troubleshooting procedures. (See DTC TABLE [L3] ).
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA Is the DTC P0131 on FREEZE FRAME DATA?	Yes	Go to the next step.
4		No	Go to troubleshooting procedures for DTC on FREEZE FRAME DATA. (See DTC TABLE [L3] ).
5	INSPECT FRONT HO2S CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the front HO2S connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 10.
5		No	Go to the next step.
6	INSPECT FRONT HO2S CIRCUIT FOR SHORT TO GROUND Turn the ignition switch off. Inspect for continuity between the following terminals and body ground: Front HO2S terminal 1A (wiring harness-side) and body ground Front HO2S terminal 1B (wiring harness-side) and body ground Front HO2S terminal 1C (wiring harness-side) and body ground Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to ground, then go to Step 10.
6		No	Go to the next step.
7	INSPECT FRONT HO2S Inspect the front HO2S. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION [L3] ). Is there any malfunction?	Yes	Replace the front HO2S, then go to Step 10. (See EXHAUST SYSTEM REMOVAL/INSTALLATION [L3] ). (See EXHAUST SYSTEM REMOVAL/INSTALLATION [L3] ).
7		No	Go to the next step.
8	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 10.
8		No	Go to the next step.
9	INSPECT FRONT HO2S CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch off. Inspect for continuity between the following circuits: Front HO2S terminal 1A (wiring harness-side) and PCM terminal 2AD (wiring harness-side) Front HO2S terminal 1B (wiring harness-side) and PCM terminal 2AC (wiring harness-side) Front HO2S terminal 1C (wiring harness-side) and PCM terminal 2Z (wiring harness-side) Is there continuity?	Yes	Go to the next step.
9		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P0131 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS or equivalent. Perform the KOEO or KOER self-test. (See KOEO/KOER SELF TEST [L3] ). Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L3] ).
10		No	Go to the next step.
11	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [L3] ). Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [L3] ).
11		No	DTC troubleshooting completed.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.