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Home >> Mazda >> 2017 >> CX-5 Grand Select, FWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> On-Board Diagnostic - Engine Control System (1 Of 5) >> DTC P0171-00: Fuel Trim System Too Lean >> Troubleshooting Diagnostic Procedure >> Intention of troubleshooting procedure

Intention of troubleshooting procedure

STEP INSPECTION RESULTS ACTION
1 PURPOSE: VERIFY IF CAUSE OF MALFUNCTION IS RELATED TO LACK OF FUEL
  • Verify the remaining amount of fuel.
  • Is there a lack of fuel?
Yes Refill the fuel, then go to Step 20.
No Go to the next step.
2 PURPOSE: DETERMINE INTEGRITY OF FUEL PRESSURE SENSOR Yes Replace the fuel distributor, then go to Step 20.
(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
3 PURPOSE: DETERMINE INTEGRITY OF HIGH PRESSURE FUEL PUMP Yes Replace the high pressure fuel pump, then go to Step 20.
(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
4 PURPOSE: VERIFY IF MALFUNCTION RELATED TO FUEL LEAK FROM FUEL SYSTEM OR RESTRICTION AFFECTS DIAGNOSTIC RESULTS
  • Inspect the fuel system pipes (low to high pressure sides) for fuel leakage and restriction.
  • Is there any malfunction?
Yes Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
No Go to the next step.
5 PURPOSE: DETERMINE INTEGRITY OF FUEL PUMP CONTROL MODULE Yes Replace the fuel pump control module, then go to Step 20.
(See FUEL PUMP CONTROL MODULE REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
6 PURPOSE: DETERMINE INTEGRITY OF FUEL PUMP UNIT Yes Replace the fuel pump unit, then go to Step 20.
(See FUEL PUMP UNIT REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
7 PURPOSE: DETERMINE INTEGRITY OF FUEL INJECTOR Yes Replace the fuel injector, then go to Step 20.
(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
8 PURPOSE: DETERMINE INTEGRITY OF PURGE SOLENOID VALVE Yes Replace the purge solenoid valve, then go to Step 20.
(See PURGE SOLENOID VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
9 PURPOSE: DETERMINE INTEGRITY OF PCV VALVE Yes Replace the PCV valve, then go to Step 20.
(See POSITIVE CRANKCASE VENTILATION (PCV) VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
10 PURPOSE: DETERMINE INTEGRITY OF MAF SENSOR Yes Replace the MAF sensor/IAT sensor No. 1, then go to Step 20.
(See MASS AIR FLOW (MAF) SENSOR/INTAKE AIR TEMPERATURE (IAT) SENSOR NO. 1 REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
11 PURPOSE: VERIFY IF MALFUNCTION RELATED TO AIR CLEANER ELEMENT AFFECTS MEASUREMENT OF INTAKE AIR AMOUNT Yes Replace the air cleaner element, then go to Step 20.
(See AIR CLEANER ELEMENT REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
12 PURPOSE: DETERMINE INTEGRITY OF MAP SENSOR Yes Replace the MAP sensor/IAT sensor No. 2, then go to Step 20.
(See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR/INTAKE AIR TEMPERATURE (IAT) SENSOR NO. 2 REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
13 PURPOSE: VERIFY IF MALFUNCTION RELATED TO INTAKE AIR SYSTEM AFFECTS DIAGNOSTIC RESULTS
  • Visually inspect for loose, cracked or damaged hoses on intake air system.
  • Is there any malfunction?
Yes Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
No Go to the next step.
14 PURPOSE: DETERMINE INTEGRITY OF ELECTRIC VARIABLE VALVE TIMING DRIVER Yes Replace the electric variable valve timing motor/driver, then go to Step 20.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
15 PURPOSE: DETERMINE INTEGRITY OF ELECTRIC VARIABLE VALVE TIMING MOTOR Yes Replace the electric variable valve timing motor/driver, then go to Step 20.
(See ELECTRIC VARIABLE VALVE TIMING MOTOR/DRIVER REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
16 PURPOSE: DETERMINE INTEGRITY OF ELECTRIC VARIABLE VALVE TIMING ACTUATOR Yes Replace the electric variable valve timing actuator, then go to Step 20.
(See ELECTRIC VARIABLE VALVE TIMING ACTUATOR, HYDRAULIC VARIABLE VALVE TIMING ACTUATOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
17 PURPOSE: DETERMINE INTEGRITY OF OCV Yes Replace the OCV, then go to Step 20.
(See OIL CONTROL VALVE (OCV) REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
18 PURPOSE: DETERMINE INTEGRITY OF A/F SENSOR Yes Replace the A/F sensor, then go to Step 20.
(See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
No Go to the next step.
19 PURPOSE: VERIFY IF MALFUNCTION RELATED TO EMISSION SYSTEM AFFECTS HO2S SIGNAL
  • Verify the exhaust gas leakage from the exhaust system. (between A/F sensor and HO2S)
  • Is there any malfunction?
Yes Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
No Go to the next step.
20 PURPOSE: VERIFICATION OF VEHICLE REPAIR COMPLETION Yes Repeat the inspection from Step 1.
No DTC troubleshooting completed.