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Home >> Chevrolet >> 2000 >> Prizm Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 1.8L >> Diagnostic Tests >> DTC P0116: ECT Sensor Circuit 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. Using scan tool, check if DTC P0115 is set. If DTC P0115 is set, diagnose DTC. See DTC P0115: ENGINE COOLANT TEMPERATURE (ECT) SENSOR CIRCUIT  . If DTC P0115 is not set, go to next step.
  3. Measure actual engine coolant temperature. Turn ignition on, with engine off. Using scan tool, monitor ECT sensor parameter. If scan tool display value is near actual engine coolant temperature, go to step  11 . If scan tool display value is not near actual engine coolant temperature, go to next step.
  4. Disconnect ECT sensor harness connector. Using scan tool, monitor ECT sensor parameter. If ECT sensor value is -40°F (-40°C), go to next step. If ECT sensor value is not -40°F (-40°C), go to step  8 .
  5. Using a fused jumper wire, connect ECT sensor input circuit to ground circuit at ECT sensor harness connector. See WIRING DIAGRAMS article. Using scan tool, monitor ECT sensor parameter. If ECT sensor value is 284°F (140°C), go to step  13 . If ECT sensor value is not 284°F (140°C), go to next step.
  6. Using a fused jumper wire, connect ECT sensor harness connector input circuit to ground. See WIRING DIAGRAMS article. Using scan tool, monitor ECT sensor parameter. If ECT sensor value is 284°F (140°C), go to next step. If ECT sensor value is not 284°F (140°C), go to step  8 .
  7. Repair open or high resistance in ECT sensor ground circuit. After repairs, go to step  14 . If circuit is okay, go to step  9 .
  8. Turn ignition off. Disconnect PCM harness connector C2. Check for short or high resistance in ECT sensor input circuit. Repair as necessary. After repairs, go to step  14 . If circuit is okay, go to next step.
  9. Check for a faulty connection at PCM and ECT harness connectors. Repair as necessary. After repairs, go to step  14 . If connections are okay, go to next step.
  10. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step  14 .
  11. Inspect engine cooling system for a faulty thermostat, low coolant level, incorrect coolant, or faulty cooling system operation. Repair as necessary. After repairs, go to step  14 . If cooling system is okay, go to next step.
  12. Using scan tool, clear DTC information. Using scan tool, place vehicle into check mode. Operate vehicle within freeze frame conditions to set DTC P0116. If DTC resets, go to next step. If DTC does not reset, see DIAGNOSTIC AIDS  .
  13. Replace ECT sensor. After replacing sensor, go to next step.
  14. 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 affected DTC(s).
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