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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 P0115: ECT Sensor Circuit >> 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. Connect scan tool to DLC. Turn ignition on, with engine off. Using scan tool, monitor ECT sensor parameter. If ECT sensor value is 284°F (140°C) or greater, go to step  5 . If ECT sensor value is less than 284°F (140°C), go to next step.
  3. Using scan tool, monitor ECT sensor parameter. If ECT sensor value is -40°F (-40°C) or less, go to step  7 . If ECT sensor value is greater than -40°F (-40°C), go to next step.
  4. Turn ignition on, with engine off. Using scan tool, clear DTC information. Using scan tool, place vehicle into check mode. Operate vehicle within freeze frame conditions. If DTC resets, go to step  2 . If DTC does not reset, see DIAGNOSTIC AIDS  .
  5. Turn ignition on, with engine off. Disconnect ECT sensor harness connector. Using scan tool, monitor ECT sensor parameter. If ECT sensor value is -40°F (-40°C), go to step  13 . If ECT sensor value is not -40°F (-40°C), go to next step.
  6. Turn ignition off. Disconnect PCM harness connector. Check for a short to ground in PCM harness connector ECT sensor input circuit. Ensure ECT sensor input circuit is not shorted to ground circuit. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step  15 . If circuit is okay, go to step  14 .
  7. Disconnect ECT sensor harness connector. Using a fused jumper wire, connect ECT sensor harness connector circuits together. Using scan tool, monitor ECT sensor parameter. If ECT sensor value is 284°F (140°C) or greater, go to step  9 . If ECT sensor value is less than 284°F (140°C), go to next step.
  8. 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) or greater, go to step  10 . If ECT sensor value is less than 284°F (140°C), go to step  11 .
  9. Check for poor connections at ECT sensor. Repair as necessary. After repairs, go to step  15 . If connections are okay, go to step  13 .
  10. Turn ignition off. Disconnect PCM harness connector. Check for open in ECT sensor ground circuit at PCM harness connector. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step  15 . If circuit is okay, go to step  12 .
  11. Turn ignition off. Disconnect PCM harness connector. Check for open or short in ECT sensor input circuit at PCM harness connector. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step  15 . If circuit is okay, go to next step.
  12. Check for poor connections at PCM. Repair as necessary. After repairs, go to step  15 . If connections are okay, go to step  14 .
  13. Replace ECT sensor. After replacing sensor, go to step  15 .
  14. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  15. 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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