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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0172 Or DTC P0175 >> Diagnostic Procedures

Diagnostic Procedures

  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed and driveability concern or rough idle is present, go to step  7. If any other DTC is present, refer to appropriate DTC test under DIAGNOSTIC TROUBLE CODE DEFINITIONS . If Continuous Memory DTCs were not present, go to next step.

  2. Identify Trigger DTC For FREEZE FRAME DATA

    If DTC P0171 or P0174 are on FREEZE FRAME DATA, go to next step. If DTC P0172 or P0175 are not on FREEZE FRAME DATA, go to trouble shooting procedure for DTC that triggered FREEZE FRAME DATA.

  3. Verify Current Input Signal Status

    Start engine. Access ECT V, MAF V, TP V and VSS PIDs as well as BARO and LONGFT using scan tool. If no signal is far out of specification, go to next step. If any signal is far out of specification during KOER, check suspect sensor and related wiring harnesses for excessive resistance. See WIRING DIAGRAMS article. Repair as necessary. After repair, go to step  9.

  4. Verify Current Input Signal Status Under Trouble Condition

    Access ECT V, MAF V, TP V and VSS PIDs while simulating FREEZE FRAME DATA condition. If there is any input signal which causes drastic changes, check condition of suspect sensor and related wiring harnesses. Repair as necessary. After repair, go to step  9. If no input signal caused any drastic changes, go to next step.

  5. Verify Current Input Signal Status Of Front HO2S

    Access O2S11 PID for P0172 or O2S21 PID for P0175. Check PID under following accelerator pedal condition (in PARK position):
    • Sudden depress of accelerator pedal (rich condition) should read more than 0.45 volt.
    • Sudden release of accelerator pedal (lean condition) should read less than 0.45 volt.

    If both PIDs are reading correctly, go to next step. If either PID read is incorrect, replace HO2S. After repair, go to step  9.

  6. Inspect Fuel Line Pressure

    Turn ignition off. Connect fuel pressure gauge. Start engine. If fuel pressure reading is 55-70 psi (380-482 kPa), go to next step. If fuel pressure is not as specified, refer to FUEL DELIVERY SYSTEM  testing under SYSTEM TESTS . After repair, go to step  9.

  7. Inspect EVAP Canister Purge Valve

    Turn ignition off. Disconnect both hoses from EVAP canister purge valve. Blow air through EVAP canister purge valve. If air passes through valve, replace EVAP canister purge valve. After repair, go to step  9. If air does not pass through valve, go to next step.

  8. Inspect PCV Valve Operation

    Inspect PCV valve for proper operation. If PCV valve is okay, go to next step. If PCV valve is not okay, replace PCV valve. After repair, go to next step.

  9. Drive Cycle

    Reconnect all disconnected connectors. Clear DTCs from PCM memory using scan tool. Perform FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  or HO2S MONITOR REPAIR VERIFICATION DRIVE CYCLE  under MONITOR REPAIR VERIFICATION DRIVE CYCLES. If same DTC is present, replace faulty PCM. If same DTC is not present, go to next step.

  10. Verify Trouble Shooting Of DTCs Completed

    Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any DTC is present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are set, trouble shooting is complete.
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