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Home >> Cadillac >> 2000 >> Seville STS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 4.6L >> Diagnostic Tests >> DTC P0121: TP Sensor Circuit Insufficient Activity >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Turn ignition on, with engine off. Using scan tool, observe TP sensor display. If TP sensor reading is about zero volts, go to next step. If TP sensor reading is not about zero volts, diagnose using DTC P0123. See DTC P0123: TP SENSOR CIRCUIT HIGH VOLTAGE .
  3. Observe TP sensor display on scan tool while slowly opening throttle. Check if TP angle increases steadily and evenly from zero to 100 percent. If TP angle increases steadily and evenly, diagnose using DTC P0106. See DTC P0106: MAP SYSTEM PERFORMANCE . If TP angle does not increase steadily and evenly, go to next step.
  4. Replace TP sensor. After replacing sensor, go to next step.
  5. Using scan tool, review and record FAIL RECORDS data. Clear DTCs. Operate vehicle within fail records conditions. Monitor SPECIFIC DTC INFO for this DTC until test runs. If scan tool indicates that this failed this ignition, go to step  2. If scan tool does not indicate that this DTC failed this ignition, system is okay.
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