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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 P0122: Throttle Position (TP) Sensor Circuit Low 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 while slowly depressing accelerator pedal . If TP voltage is less than .1 volt, go to next step. If TP voltage is .1 volt or more, problem is intermittent (not current).
  3. Disconnect TP sensor connector. Connect a jumper wire between harness connector terminals "A" (Light Green/Red wire) and "C" (Green/Black wire). Using scan tool, access TP V. If TP voltage is more than 4.8 volts, go to next step. If TP voltage is 4.8 volts or less, go to step  8.
  4. Turn ignition off. Check continuity between TP sensor terminals "A" and "C". If continuity is present, check sensor terminal and harness connector terminal "C". Repair as necessary. After repair, go to step  8. If continuity is not present, replace TP sensor. Go to step  8.
    NOTE: If DTC P0107 and P0452 are present, check reference voltage. See REFERENCE VOLTAGE TEST .
  5. Turn ignition on. Check voltage at harness connector terminal "A" (Light Green/Red wire). If 4.5-5.5 volts are present, go to next step. If 4.5-5.5 volts are not present, repair open circuit in Light Green/Red wire between EGR boost sensor and PCM connector No. 2 terminal "I". Go to step  8.
  6. Turn ignition off. Disconnect PCM connectors. Check continuity of Green/Black wire between TP sensor harness connector terminal "C" and PCM connector No. 3 terminal "E". If continuity is present, go to next step. If continuity is not present, repair open circuit. Go to step  8.
  7. Check continuity between PCM connector No. 3 terminal "E" (Green/Black wire) and ground. If continuity is not present, Repair short between Black/Red wire and Green/Black wire. After repair, go to next step. If continuity is present, repair short to ground. Go to next step.
  8. Connect all connectors. Start engine. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. If same DTC is present, replace PCM. If same DTC is not present, go to next step.
  9. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. If any other DTC is present, diagnose and repair. If no DTC is present, testing is complete.
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