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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 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. Inspect TP sensor and PCM harness connectors. Repair as needed and go to step  6. If connectors are okay, go to next step.
  2. 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 open in wire between PCM connector terminal No. 90 and TP sensor. See Figure. If wire is okay, check for loose or corroded connector terminals. Repair as needed and go to step  6.
  3. Turn ignition off. Disconnect PCM connector. Check continuity in wire between terminal "C" on TP harness connector and terminal No. 89 on PCM harness connector. See Figure. If continuity does not exits, check for open in wire. Repair as needed and go to step  6. If continuity is present, go to next step.
  4. Check continuity between PCM connector terminals No. 89 and 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. See Figure. If continuity is present, check for short to ground is suspect wire. Repair as needed and go to step  6. If continuity is not present, go to next step.
  5. 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.
  6. 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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