Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSMAZDA20105 SPORT, 2.3 L, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 431 (ON-BOARD DIAGNOSTIC (ENGINE CONTROL SYSTEM 13BMSP])DTC P0171DIAGNOSTIC PROCEDURE

2010 Mazda 5 Sport, 2.3 L, Standard

Diagnostic procedure

2010 Mazda 5 Sport, 2.3 L, StandardSECTION Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0171 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 (Fuel system 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 CODE OR STORED DTC Turn the ignition switch off, then to the ON position (Engine off). Verify the related PENDING CODE or stored DTCs. Are other DTCs present?	Yes	If misfire DTC is present, go to Step 8. If other DTC is present, go to the appropriate DTC inspection. (See DTC TABLE .)
3		No	If drive ability concern is present, go to Step 8. If other, go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA Is DTC P0171 on FREEZE FRAME DATA?	Yes	Go to the next step.
4		No	Go to the FREEZE FRAME DATA DTC inspection. (See DTC TABLE .)
5	VERIFY CURRENT INPUT SIGNAL STATUS Connect the WDS or equivalent to the DLC-2. Verify the following PIDs. (See PCM INSPECTION .) APP ECT MAF TP VSS Are the PIDs normal?	Yes	Go to the next step.
5		No	Inspect the malfunctioning part according to the inspection results. Then go to Step 24.
6	VERIFY CURRENT INPUT SIGNAL STATUS UNDER FREEZE FRAME DATA CONDITION Connect the WDS or equivalent to the DLC-2. Verify the following PIDs under the FREEZE FRAME DATA condition. (See PCM INSPECTION .) APP ECT MAF TP VSS Are the PIDs normal?	Yes	Go to the next step.
6		No	Inspect the malfunctioning part according to the inspection results. Then go to Step 24.
7	VERIFY CURRENT INPUT SIGNAL STATUS OF FRONT HO2S Connect the WDS or equivalent to the DLC-2. Start the engine and warm it up completely. Access the O2S11 PID. Read the O2S11 PID under following accelerator pedal condition (in PARK or NEUTRAL). Less than 1 mA when accelerator pedal is suddenly depressed (rich condition). More than 1 mA just after release of accelerator pedal (lean condition) Is the PID normal?	Yes	Inspect for air suction due to cracks, damage or loose parts in the following areas: From air cleaner to throttle body From throttle body to intake manifold Vacuum hoses NOTE: Engine speed may change when rust penetrating agent (cab cleaner etc.) is sprayed on the air suction area. Repair or replace the malfunctioning part, then go to Step 24.
7		No	Go to the next step.
8	INSPECT EXHAUST SYSTEM FOR EXHAUST GAS LEAKAGE Visually inspect exhaust gas leakage in the exhaust system. Is there exhaust gas leakage?	Yes	Repair or replace the malfunctioning part, then go to Step 24.
8		No	Replace the front HO2S, then go to Step 24. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
9	VERIFY CURRENT INPUT SIGNAL STATUS OF MAF SENSOR Connect the WDS or equivalent to the DLC-2. Start the engine. Access the MAF PID. Verify that the MAF PID changes quickly according to RPM when the engine is raced. Is the PID normal?	Yes	Go to the next step.
9		No	Replace the MAF/IAT sensor, then go to Step 24. (See MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION .)
10	INSPECT INTAKE-AIR SYSTEM FOR EXCESSIVE AIR SUCTION Visually inspect for looseness, cracks or damaged hoses in the intake-air system. Is there any malfunction?	Yes	Repair or replace the malfunctioning part, then go to Step 24.
10		No	Go to the next step.
11	INSPECT FUEL LINE PRESSURE Perform the "FUEL LINE PRESSURE INSPECTION". (See FUEL LINE PRESSURE INSPECTION .) Is there any malfunction?	Yes	If the fuel line pressure is too low, go to the next step. If the fuel line pressure is too high, replace the fuel pump unit, then go to Step 24. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
11		No	Go to Step 13.
12	INSPECT FUEL SYSTEM FOR FUEL LEAKAGE Visually inspect for fuel leakage in the fuel system. Is there fuel leakage?	Yes	Repair or replace the malfunctioning part, then go to Step 24.
12		No	Replace the fuel pump unit, then go to Step 25. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
13	INSPECT IGNITION COIL OPERATION AND HIGH-TENSION LEAD WITH TIMING LIGHT Inspect the blinking condition on each high-tension lead using timing light at idle. Do all the high-tension leads show blinking condition?	Yes	Go to Step 17.
13		No	Go to the next step.
14	INSPECT HIGH-TENSION LEAD OF NON BLINKING HIGH-TENSION LEAD Inspect the high-tension leads. (See HIGH-TENSION LEAD INSPECTION .) Is there any malfunction?	Yes	Replace the malfunctioning high-tension lead, then go to Step 24. (See HIGH-TENSION LEAD REMOVAL/INSTALLATION .)
14		No	Go to the next step.
15	INSPECT IGNITION COIL POWER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND Turn the ignition switch to the ON position (Engine off). Measure the voltage between ignition coil terminal C (wiring harness-side) and body ground. Is the voltage B+ ?	Yes	Go to the next step.
15		No	Repair or replace the wiring harness for a possible open circuit or short to ground, then go to Step 24.
16	INSPECT IGNITION COIL Inspect the ignition coil. (See IGNITION COIL INSPECTION .) Is there any malfunction?	Yes	Replace the ignition coil, then go to Step 24. (See IGNITION COIL REMOVAL/INSTALLATION .)
16		No	Go to the next step.
17	INSPECT AIR SYSTEM OPERATION Perform the "AIR System Inspection". (See SECONDARY AIR INJECTION (AIR) SYSTEM INSPECTION .) Does AIR system operate properly?	Yes	Go to the next step.
17		No	Repair or replace malfunctioning part according to the inspection results. Then go to Step 23.
18	INSPECT ENGINE COMPRESSION Inspect the engine compression. (See COMPRESSION INSPECTION .) Is there any malfunction?	Yes	Go to the next step.
18		No	Go to Step 23.
19	INSPECT METERING OIL PUMP Inspect the metering oil pump. (See METERING OIL PUMP REMOVAL/INSTALLATION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Overhaul or replace the engine. Then go to Step 24.
19		No	Go to the next step.
20	INSPECT ENGINE OIL CONDITION Inspect the engine oil condition. Is the engine oil condition normal?	Yes	Go to the next step.
20		No	Replace the engine oil. Inspect the ECT sensor and related harnesses. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) Overhaul or replace the engine. Then go to Step 24.
21	INSPECT OIL PRESSURE Inspect the oil pressure. (See OIL PRESSURE INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Overhaul or replace the engine. Then go to Step 24.
21		No	Go to the next step.
22	INSPECT OIL PASSAGE Inspect the oil pipe between metering oil pump and metering oil nozzle. Is there any malfunction?	Yes	Inspect and repair for leakage or clogging in the engine oil passage. Overhaul or replace the engine. Then go to Step 24.
22		No	Overhaul or replace the engine. Then go to the next step.
23	INSPECT FUEL INJECTOR Inspect the fuel injector. (See FUEL INJECTOR INSPECTION .) Is there any malfunction?	Yes	Replace the fuel injector, then go to the next step. (See FUEL INJECTOR REMOVAL/INSTALLATION .)
23		No	Go to the next step.
24	VERIFY TROUBLESHOOTING OF DTC P0171 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the WDS or equivalent. Perform the "DRIVE MODE 1". (See OBD-II DRIVE MODE .) Is the PENDING CODE same as the DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION .)
24		No	Go to the next step.
25	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
25		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.