LEMON Manuals: Even more car manuals for everyone
Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 61 (Engine Controls [Self-Diagnostics 3.0L]) >> Diagnostic Tests >> DTC P0172 Or DTC P0175 >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
  1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
  2. Verify Related Repair Information Availability -  Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
  3. Verify Related Pending Code Or Stored DTCs -  Turn ignition off, then on (engine off). Verify pending code or stored DTCs using WDS or equivalent. If any other DTC is present, go to appropriate DTC trouble shooting procedure. Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no other DTCs are present, go to next step.
  4. Identify Trigger DTC For FREEZE FRAME DATA -  If DTC P0172 or P0175 are on FREEZE FRAME DATA, go to next step. If DTC P0172 or P0175 triggered FREEZE FRAME DATA, go to appropriate DTC trouble shooting procedure for DTC that triggered FREEZE FRAME DATA. Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  5. Verify Current Input Signal Status (Ignition On/Engine Idle) -  Access ECT, MAF, TP_REL and VSS PIDs using WDS or equivalent. If no signal is far out of specification when ignition is on and engine running, go to next step. If any signal is far out of specification when ignition is on and engine running, check for faulty sensor and excessive resistance in related wiring harness. Repair or replace if necessary. After repair, go to step  11.
  6. Verify Current Input Signal Status Under Trouble Condition -  Inspect same PIDs as in step  5 while simulating FREEZE FRAME DATA condition. If no input signal causes drastic changes, go to next step. If any input signal causes drastic changes, check for faulty sensor and related wiring harness. Repair or replace if necessary. After repair, go to step  11.
  7. Verify Current Input Signal Status Of Right & Left Front HO2S -  Access O2S11 for P0171 or O2S21 for P0174 PID using WDS or equivalent. Check PID under following accelerator pedal condition in Park (ATX) or Neutral (MTX).
    • Rich Condition -  0.45 volt or more when the accelerator pedal is suddenly depressed
    • Lean Condition -  0.45 volt or less just after release of accelerator pedal
    If PID reading is okay, go to next step. If PID reading is not as specified, replace suspected HO2S. After repair, go to step  11.
  8. Inspect Fuel Line Pressure -  Turn ignition off. Connect fuel gauge on fuel pipe. Start engine and run it at idle. Inspect fuel line pressure. Refer to FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel line pressure is okay, go to next step. If fuel line pressure is excessive, replace fuel pump unit. Refer to FUEL PUMP under FUEL SYSTEM in REMOVAL & INSTALLATION article. After repair, go to step  11.
  9. Inspect Long Term Fuel Trim -  Turn ignition off. Disconnect purge hose from intake manifold and plug opening end of hose and intake manifold. Access following PIDs:
    • For P0172: LONGFT1
    • For P0175: LONGFT2
    If PID did not shift to positive value, go to next step. If PID shifted to positive value, inspect purge solenoid valve. Refer to FUEL EVAPORATIVE SYSTEM - EXCEPT PROTEGE & PROTEGE5 under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Repair or replace purge solenoid valve if necessary. After repair, go to step  11.
  10. Inspect PCV Valve Operation -  Inspect PCV valve operation. Refer to POSITIVE CRANKCASE VENTILATION under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PCV valve is okay, go to next step. If PCV valve is faulty, replace PCV valve. After repair, go to next step.
  11. Verify Trouble Shooting Of DTC P0171 Or P0174 Is Completed -  Make sure to reconnect all disconnected connectors. Clear DTC from memory using WDS or equivalent. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Run MODE 1 - PCM ADAPTIVE MEMORY PRODUCE DRIVE MODE , MODE 2 - EGR SYSTEM REPAIR VERIFICATION DRIVE MODE  and MODE 3 - HO2S HEATER, HO2S & TWC REPAIR VERIFICATION DRIVE MODE  . Stop vehicle and access ON BOARD READINESS TEST to inspect DRIVE MODE completion status. Verify FUEL_EVAL PID changes to YES. If not, run DRIVE MODE again. Access PENDING CODE. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
  12. Verify After Repair Procedure -  Using scan tool, perform After Repair Procedure. See AFTER REPAIR PROCEDURE . If any DTCs are present, go to appropriate DTC inspection. Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are present, trouble shooting is complete.
Fig 1: Identifying Powertrain Control Module (PCM) Harness Connector Terminals
G00193634Courtesy of MAZDA MOTORS CORP.
scientia non olet · About LEMON Manuals