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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 P0123: Throttle Position (TP) Sensor Circuit High Input >> 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. Turn ignition on. Using scan tool, access PID/DATA MONITOR. Record PID data for TP V. Slowly depress accelerator pedal to wide open throttle. Voltage should increase evenly as throttle opening is increased. If voltage is more than 4.8 volts, go to next step. If voltage is 4.8 volts or less, problem is intermittent (not current).
  3. Turn ignition off. Disconnect TP connector. Check connector and terminals. If no problem is found, go to next step. If problem is found, repair as needed and go to step  9.
  4. Check resistance between TP sensor terminals "A" and "B" Resistance should be 2500-5000 ohms. Check resistance between TP sensor terminals "B" and "C" Resistance should be 200-1100 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace TP sensor. Go to step  9.
  5. Check continuity between TP harness connector terminal "B" (Black/Red wire) and ground. If continuity exists, go to next step. If continuity does not exist, repair as needed and go to step  9.
  6. Check continuity of Green/Black wire between terminal "C" on TP harness connector and PCM harness connector No. 3 terminal "E". If continuity does not exist, go to next step. If continuity exists, go to step  8.
  7. Disconnect PCM connectors. Check connectors and terminals. If any problem is found, repair as needed and go to step  9. If no problem is found, go to step  9.
  8. Check continuity between TP sensor harness connector terminals "A" (Light Green wire) and "C" (Green/Black wire). If continuity is not present, go to next step. If continuity is present, repair short between circuits and go to next step.
  9. Connect all connectors. Start engine. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. Using scan tool, access PID/DATA MONITOR. Record PID data for TP V. Voltage should be .1-4.8 volts. If same DTC is not present, go to next step. If same DTC is present, replace PCM. Go to next step.
  10. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. If any DTC is present, diagnose and repair. If no DTC is present, testing is complete.
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