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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 48 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0172 Or DTC P0175 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Mazda B4000, 2002 Mazda B3000, and 2002 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed and any other DTCs are present, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS  . For DTCs P0172 or P0175, go to next step.
  2. Read Freeze Frame Data. If DTC P0172 or P0175 data is stored in Freeze Frame Data, go to next step. If data from any other DTC is stored in Freeze Frame Data (meaning a more recent DTC is stored), repair other stored DTC(s) first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .

  3. Verify Current Input Signal Status

    With KOER, access ECT V, MAF V, TP V, VSS V, BARO V and LONGFT V PIDs. Observe signals. If signals are within specification during KOER, go to next step. If any signal is far out of specification during KOER, inspect suspect sensor and check for excessive resistance in related wiring harness. Repair or replace as necessary. 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 conditions. Observe signals. If all signals are okay, go to next step. If any signal has drastic changes, inspect suspect sensor and related wiring harness. Repair or replace as necessary. Go to step  9 .

  5. Verify Current Input Signal Status Of Front HO2S

    For DTC P0172, access O2S11 PID. For DTC P0175, access O2S21 PID. For either DTC, check PID under the following accelerator pedal conditions in Park:
    • Depress accelerator suddenly (rich condition). Voltage should be more than 0.45 volts.
    • Release accelerator suddenly (lean condition). Voltage should be less than 0.45 volts.
    If voltage is okay, go to next step. If voltage is not okay, replace faulty HO2S. Go to step  9 .

  6. Inspect Fuel Line Pressure

    Turn ignition off. Connect a fuel pressure gauge to vehicle. With KOER fuel pressure should be 30-65 psi (207-448 kPa). If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, replace faulty fuel pump. 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 does not pass through valve, go to next step. If air passes through valve, replace faulty EVAP canister purge valve. Go to step  9 .

  8. Inspect PCV Valve Operation

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

  9. Drive Cycle

    Reconnect all electrical connectors. Using scan tool, clear DTC memory. Perform HO2S MONITOR REPAIR VERIFICATION DRIVE CYCLE  or FUEL OR MISFIRE MONITOR REPAIR VERIFICATION DRIVE CYCLE  in MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. Using scan tool, retrieve DTCs. If same DTC is not present, go to next step. If same DTC is present, replace faulty PCM. Go to next step.

  10. Verify Trouble Shooting Of DTCs Completed

    Make sure all electrical connectors are reconnected. Clear DTCs from PCM memory using scan tool. Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If the same DTC is present, replace faulty PCM. Repeat QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no DTCs are present, test is complete.
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