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Home >> Mazda >> 2000 >> MX-5 Miata Base, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1135: Front O2 Sensor Heater Circuit Low >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Ensure FREEZE FRAME PID data has been recorded. Check service bulletins. Go to next step.
  2. Inspect front O2 sensor and harness connector terminals. If no problem is found, go to next step. If problem is found, repair as necessary and go to step  8.
  3. Check resistance of front O2 sensor between terminals "C" and "D". If resistance is 15.7 ohms, go to next step. If resistance is not 15.7 ohms, replace O2 sensor and go to step  8.
  4. Disconnect front oxygen sensor. Turn ignition on. Check voltage at O2 sensor harness connector terminal "C" (Black/White wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open or short in circuit between ignition switch and O2 sensor. Go to step  8.
  5. Inspect PCM and harness connector terminals. If no problem is found, go to next step. If problem is found, repair as necessary and go to step  8.
  6. Check continuity between front O2 sensor harness connector terminal "D" (Violet/Yellow wire) and ground. If continuity is not present, go to next step. If continuity is present, repair short to ground. Go to step  8.
  7. Check continuity of Violet/Yellow wire between front O2 sensor harness connector terminal "D" and PCM connector No. 1 terminal "U". If no problem is found, go to next step. If problem is found, repair as necessary and go to next step.
  8. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. If DTC is not pending, go to next step. If DTC is pending, replace PCM. After repair, go to next step.
  9. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. If any DTC is present, go to appropriate test. If DTC is not present, test is complete.
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