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Home >> Chevrolet >> 2002 >> Impala LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0116: ECT Sensor Circuit Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Is the cooling system low on coolant? If yes, repair coolant loss. If no, go to next step.
  3. Turn off the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor. Turn on the ignition, with the engine off. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step  5.
  4. Turn off the ignition. Disconnect the IAT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the IAT sensor. Turn on the ignition, with the engine off. Observe the IAT sensor temperature with a scan tool. Does the scan tool indicate that the IAT sensor temperature is more than 280°F (138°C)? If yes, go to step  8. If no, see DIAGNOSTIC AIDS .
  5. Turn off the ignition. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and of a known-good ground. Turn on the ignition, with the engine off. Observe the ECT sensor temperature with a scan tool. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to next step. If no, go to step  7.
  6. Test the ECT sensor low reference circuit for a high resistance or for an open. Repair the circuit as necessary. After repairs, go to step  11.
  7. Test the ECT sensor signal circuit for a high resistance or for an open. Repair the circuit as necessary. After repairs, go to step  11.
  8. Remove the ECT sensor. Suspend the ECT sensor and a thermometer in a pan of water. Place the pan on a burner or on a hot plate. Test the resistance of the ECT sensor through the specified range of temperatures. See TEMPERATURE VS RESISTANCE table in appropriate SENSOR OPERATING RANGE CHARTS article. Do the resistance and temperature closely match the Temperature vs Resistance table? If yes, go to next step. If no, go to step  10.
  9. Reinstall the ECT sensor. After installation, see DIAGNOSTIC AIDS .
  10. Replace the ECT sensor. After repairs, go to next step.
  11. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within Conditions for Running DTC. Does DTC run and pass? If yes, go to next step. If no, go to step  2.
  12. Using scan tool, observe stored information. Does scan tool displays any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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