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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 P1123: TP Sensor Input Is Stuck Open >> 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. Clear DTCs. Start engine. Using scan tool, access PID/DATA MONITOR. Record PID data for TP, MAF and RPM. With MAF PID less than .7 lb/min. and engine speed more than 500RPM, TP PID should be less than 50 percent. If data is within specification, go to next step. If data is not within specification, go to step  4.
  3. Using scan tool, access PID/DATA MONITOR. Record PID data for MAF V. Drive vehicle. If data is not within specification, check MAF sensor. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. Replace as needed and go to step  8. If data is within specification, problem is not current (intermittent).
  4. Check TP 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.
  5. Check resistance between TP sensor harness connector terminal "B" (Black/Red wire) and ground. If no resistance is present, go to next step. If resistance is found, repair poor connection or open circuit. After repair, go to step  8.
  6. using ohmmeter connected to TP sensor terminals "A" and "C", check TP sensor resistance. If resistance changes smoothly when throttle is opened, go to next step. If resistance does not change smoothly, replace TP sensor. Go to step  8.
  7. Check PCM and harness connector terminals. If no problem is found, go to next step. If problem is found, repair as necessary and go to next step.
  8. Connect all connectors. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. Start engine. Using scan tool, access PID/DATA MONITOR. Record PID data for TP, MAF and RPM. With MAF PID less than .7 lb/min. and engine speed more than 500 RPM, TP PID should be less than 50 percent. 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 no DTC is present, test is complete.
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