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Home >> Mazda >> 2001 >> MX-5 Miata Base, Standard >> Repair and Diagnosis >> 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 DATA has been recorded. Check for related service bulletins. Repair as necessary and go to next step.
  2. Turn ignition on. Using scan tool, access TP V PID data. Slowly depress accelerator pedal . If TP V PID is more than 4.8 volts, go to next step. If TP V PID is 4.8 volts or less, problem is intermittent. See TROUBLE SHOOTING - NO CODES article.
  3. Turn ignition off. Disconnect TP connector. Check connector for loose or damaged terminals, poor contact or corrosion. If no problem is found, go to next step. If problem is found, repair as necessary and go to step  8.
  4. Check resistance between TP sensor terminals "A" and "B". See Figure. Resistance should be 2.5-5 k/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 and go to step  8.
  5. Check for continuity between TP harness connector terminal "B" (Black/Red wire) and ground. If continuity is present, go to step  7. If continuity is not present, go to next step.
  6. Disconnect appropriate PCM connectors. Check connector for loose or damaged terminals, poor contact or corrosion. If any problem is found, repair as necessary and go to step  8. If no problem is found, go to step  8.
  7. Check for continuity between TP sensor harness connector terminals "A" (Light Green/Red wire) and "C" (Green/Black wire). See Figure. If continuity is not present, go to next step. If continuity is present, repair short between circuits and go to next step.
  8. Reconnect all connectors. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine and allow it to reach normal operating temperature. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P0123 is present, replace PCM and go to next step. On vehicles equipped with immobilizer system, reprogram ignition key identification numbers. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. If DTC P0123 is not present, go to next step.
  9. Cycle ignition from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.
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