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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 60 (Engine Controls [Self-Diagnostics 2.3L]) >> Diagnostic Tests >> DTC P0038: Rear Ho2S Heater Circuit - High Input >> 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 Rear HO2S Connector For Poor Connection -  Turn ignition off. Disconnect rear HO2S 4-pin harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunction is not found, go to next step. If any malfunction is present, repair or replace terminal. After repair, go to step  7.
  4. Inspect Rear HO2S Heater -  Inspect rear HO2S heater. Refer to HEATED OXYGEN SENSOR under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If rear HO2S heater is okay, go to next step. If rear HO2S heater is faulty, replace the rear HO2S. After repair, go to step  7.
  5. Inspect PCM Connector For Poor Connection -  Turn ignition off. Disconnect PCM 30-pin harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunctions are not found, go to next step. If any malfunctions are found, repair terminal. After repair, go to step  7.
  6. Inspect Rear HO2S Heater Control Circuit For Short To Power -  Turn ignition, on engine off. Measure voltage between rear HO2S 4-pin harness connector terminal "D" and body ground. See Figure. If battery voltage is not present, go to next step. If battery voltage is present, repair or replace harness for short to power circuit in White/Green wire between rear HO2S 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "4D". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
  7. Verify Trouble Shooting Of DTC P0038 Is Completed -  Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. 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.
  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.
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