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Home >> Chevrolet >> 2000 >> Metro Base, 2D Hatchback >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 1.0L & 1.3L >> Diagnostic Tests >> DTC P0121: TP Sensor System Performance >> 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. Ensure engine is at normal operating temperature. Turn ignition on, with engine off. Connect scan tool to DLC. Using scan tool, monitor TP sensor voltage parameter. If TP sensor value is 0.2-1.0 volt with throttle at idle position, and 3.0-4.8 volts at WOT, see DIAGNOSTIC AIDS . If voltage is not as specified, go to next step.
  3. Disconnect TP sensor electrical connector. Using DVOM connected to ground, backprobe PCM 16-pin connector TP sensor input circuit. See WIRING DIAGRAMS article. If voltage reading is 4-5 volts, go to next step. If voltage reading is not 4-5 volts, go to step  5.
  4. Using DVOM, check voltage of TP sensor input circuit at TP sensor connector (harness side) to ground. See WIRING DIAGRAMS article. If voltage reading is 4-5 volts, go to step  7. If voltage reading is not 4-5 volts, go to step  6.
  5. Check for high resistance, short to voltage or short to ground in TP sensor input circuit. Check TP sensor ground circuit for a poor connection. Repair as necessary. After repairs, go to step  9. If circuits are okay, go to step  8.
  6. Check for an open in TP sensor input circuit between TP sensor and PCM. Repair as necessary. After repairs, go to step  9. If circuit is okay, go to step  8.
  7. Replace TP sensor. After replacing sensor, go to step  9.
  8. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  9. After repairs, using scan tool, clear DTC information. Road test vehicle within freeze frame conditions that set DTC. Check for DTCs. If no DTCs are stored, repair is complete. If any DTCs are stored, diagnose DTC(s).
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