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DTC P0125 - Excessive Time To Enter Closed Loop Fuel Control

NOTE: For terminal identification, see TERMINAL IDENTIFICATION in SELF-DIAGNOSTICS section. For circuit and wire color identification, see WIRING DIAGRAMS article.
  1. Disconnect front Heated Oxygen Sensor (HO2S) connector. Connect Test Harness (MD991223) to front HO2S. Using DVOM, check continuity between test harness terminals No. 3 and 4. If continuity exists, go to next step. If continuity does not exist, replace front HO2S.
  2. Start and warm engine until engine coolant temperature is 176°F (80°C) or more. Connect jumper wires between battery positive and test harness terminal No. 3 and between battery negative and test harness terminal No. 4. Connect DVOM between test harness terminals No. 1 and 2. Check front HO2S output voltage, while repeatedly racing engine. If voltage is 0.6-1.0 volt, go to next step. If voltage is not as specified, replace front HO2S.
  3. Check connectors and wiring harness between front HO2S and PCM. Repair connectors or wiring as necessary. If wiring and connectors are okay, Go to next step.
  4. Disconnect fuel injector connector. Check resistance across fuel injector terminals. Resistance at 68°F (20°C) should be 13-16 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace fuel injector.
  5. Using stethoscope, check injector operating sound during cranking or at idle. Check that frequency of operating sound increases as engine RPM increases. If injectors are okay, go to next step. If no operating sound is heard from an injector, check injector drive circuit. If drive circuit is okay, injector or PCM is suspect.
  6. Check fuel injector connectors, PCM connector and wiring harness between PCM and injector connectors. If wiring and connectors are okay, perform fuel pressure test. See FUEL SYSTEM in BASIC TESTING article. If fuel pressure is okay, go to next step.
  7. Check for air being drawn into air intake or exhaust system. check for exhaust leaks at HO2S fittings, exhaust manifold, or front pipes.Check for fuel filter and/or fuel line blockage. Check fuel pump for poor fuel supply. If no problems are found, replace PCM.
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