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Home >> Mazda >> 1999 >> Protege ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 1.8L >> 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. Verify stored DTCs and pending codes. If DTCs P0108, P0113, P0118, P0134 or P0453 are present, go to next step. If listed DTCs are not present, go to step  8.
  2. Check for open or short to power in wire between PCM harness connector terminal No. 91 and EGR boost sensor, IAT sensor, ECT sensor, front heated oxygen sensor and fuel tank pressure sensor connectors, individually. See Figure. Also check for open or short to power between negative battery terminal and PCM connector terminal No. 24 (Black/White wire), No. 51 (Black/White wire), No. 76 (Black/White wire), No. 77 (Black/White wire) and No. 103 (Black/Red wire), individually. Repair as needed and go to step  8.
  3. Turn ignition off. Disconnect TP sensor connector. Turn ignition on. Measure voltage between ground and terminal "A" on TP sensor harness connector. If 5 volts is present, go to next step. If 5 volts is not present, check for short to power in wire between PCM connector terminal No. 90 and TP sensor. See Figure. Repair as needed and go to step  8.
  4. Turn ignition off. Disconnect PCM connector. Check for continuity in wire between terminal "B" on TP sensor connector and PCM harness connector terminal No. 91. See Figure. If continuity is present, go to next step. If continuity is not present, check for open in wire between TP sensor and PCM. Repair as needed and go to step  8.
  5. Check for continuity PCM harness connector terminals No. 91, and No. 71 (White/Black wire) and No. 97 (White wire), individually. See Figure. If continuity is present, check for short to power in suspect wire and go to step  8. If continuity is not present, go to next step.
  6. Check for continuity PCM harness connector terminals No. 89, and No. 71 (White/Black wire) and No. 97 (White wire), individually. See Figure. If continuity is present, check for short to power in suspect wire and go to step  8. If continuity is not present, go to next step.
  7. Reconnect TP sensor and PCM connectors. Using scan tool, access PID/DATA MONITOR. Record PID readings for TP V. Turn ignition on. Slowly depress accelerator pedal to wide open throttle. TP V PID should increase evenly as throttle opening is increased. If TP V PID changes as specified, go to next step. If TP V PID does not change as specified, replace TP sensor and go to next step.
  8. Erase DTC. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION - PROTEGE 1.6L & 1.8L article. If DTC is present, replace PCM. If DTC is not present, intermittent poor harness connection may have caused DTC to originally set.
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