LEMON Manuals: Even more car manuals for everyone
Home >> Mazda >> 2013 >> 5 Grand Touring >> Repair and Diagnosis >> External Pages >> Different car >> Section 59 (Engine Controls [Self-Diagnostics 3.0L]) >> Diagnostic Tests >> DTC P0126 Or DTC P0128 >> 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. Inspect For Other DTCs -  If any other DTCs been stored, perform appropriate DTC troubleshooting procedure. Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS . After repair, go to next step. If no other DTCs are present, go to next step.
  4. Inspect Coolant Thermostat For Whether Stuck Open -  Remove coolant thermostat and ensure it is not stuck open. Replace as necessary and go to next step. If thermostat is okay, check ECT sensor operation. Refer to ENGINE COOLANT TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Replace ECT sensor if necessary. After repair, go to next step. If coolant thermostat is faulty, replace coolant thermostat. After repair, go to next step.
    5. NOTE: If workshop interior and outdoor temperature difference is significant, PCM might not operate thermostat monitor. In order for the PCM to operate thermostat monitor, manufacturer recommends allowing engine to cool with vehicle outside workshop.
  5. Verify Monitoring Condition For Repair Verification -  Reconnect all connections. Allow engine to cool. Turn ignition on, engine off. Clear DTC from PCM memory using WDS or equivalent. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Access ECT, IAT PIDs and make sure that each value is within following specifications.
    • ECT: Less than 97°F (36°C) (for P0128 only)
    • IAT: More than 14°F (-10°C)
    • Difference between ECT and IAT: Less than 43°F (6°C)
    If all PID values are as specified, for DTC P0126, go to next step. For DTC P0128, go to step  7. If any PID value is out of specification, take corrective action (e.g. cool down engine). Repeat this step.
    6. NOTE: This step requires actual driving. DO NOT use chassis roller for this test. During test drive, constant speed should be maintained, although 2 or 3 stops during every 5 minutes of driving time (e.g. for traffic signals) is acceptable. Stop-and-go (e.g. in case of traffic congestion) is not acceptable during test period. Test period depends on engine coolant temperature at engine start. The warmer the engine coolant, the less time required for test. For example, if engine coolant temperature is 14°F (-10°C), monitoring period is 38 minutes, but if engine coolant temperature is 86°F (30°C), monitoring period is only 8 minutes.
  6. Verify Trouble Shooting Of DTC P0126 Is Completed -  Start engine. Turn off HVAC and all electrical accessories. Access DIAGNOSTIC MONITORING TEST RESULTS using WDS or equivalent and monitor TEST# 10:E1:81 (ECT). Drive vehicle 25-62 MPH until TEST value changes. If measured value is not more than minimum value, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to step  8. If measured value is more than minimum value, go to step  8.
    7. NOTE: This test requires actual driving. Chassis roller cannot be used for this test. During test drive, constant speed should be maintained, although 2 or 3 stops (e.g. for traffic signals) is acceptable. Stop-and-go (e.g. in case of traffic congestion) is not acceptable during test period.
  7. Verify Trouble Shooting Of DTC P0128 Is Completed -  Start engine. Turn off HVAC and all electrical accessories. Access DIAGNOSTIC MONITORING TEST RESULTS using WDS or equivalent and monitor TEST# 10:E1:80 (Heat Radiation Ratio) or TEST# 10:E1:81 (ECT). Drive vehicle 25-62 MPH until TEST value changes. If measured value is not more than minimum value, 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. If measured value is more than minimum value, go to next step.
  8. 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.
scientia non olet · About LEMON Manuals