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Home >> Cadillac >> 2003 >> DeVille DHS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0116: ECT Sensor Performance >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Is the cooling system low on coolant? If yes, repair and refill cooling system. If no, go to next step.
  3. Turn ignition off. 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 ignition on, with engine off. Observe the ECT SENSOR parameter with a scan tool. Does the scan tool indicate that the ECT SENSOR parameter is more than 280°F (138°C)? If yes, go to next step. If no, go to step  5.
  4. Disconnect the IAT sensor. Connect a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the IAT sensor. Observe the IAT SENSOR parameter with a scan tool. Does the scan tool indicate that the IAT SENSOR parameter is more than 280°F (138°C)? If yes, go to step  8. If no, see DIAGNOSTIC AIDS .
  5. Disconnect the ECT sensor. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and a known-good ground. 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 low reference circuit for a high resistance or an open. Did you find and correct the condition? If yes, go to step  11. If no, see DIAGNOSTIC AIDS .
  7. Test the signal circuit for a high resistance or an open. Did you find and correct the condition? If yes, go to step  11. If no, see DIAGNOSTIC AIDS .
  8. Remove ECT sensor. Suspend the ECT sensor and a thermometer in a pan of water. Place the pan on a burner or hot plate. Test the resistance of the ECT sensor through 50-194°F (10-90°C). See appropriate SENSOR OPERATING RANGE CHARTS article. Does 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. When complete, see DIAGNOSTIC AIDS .
  10. Test for an intermittent and/or poor connections at the ECT sensor. Did you find and correct the condition? If yes, go to step  12. If no, go to next step.
  11. Replace ECT sensor. See ENGINE COOLANT TEMPERATURE SENSOR under SENSORS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to next step.
  12. Clear the DTCs with a scan tool. Turn off the ignition for 30 seconds. Start the engine and operate vehicle within the Conditions For Running DTC. You may also operate vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to step  2. If no, go to next step.
  13. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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