LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2000 >> Protege DX, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 1.6L >> Diagnostic Trouble Code Tests >> DTC P0117: Engine Coolant Temperature (ECT) Sensor Circuit Low Input >> Diagnosis & Repair Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis & Repair Procedure

  1. Ensure FREEZE FRAME PID data has been recorded. Check service bulletins. Go to next step.
  2. Start engine. Warm engine to operating temperature. Using scan tool, check ECT V PID. If ECT voltage is less than .2 volt, go to next step. If ECT voltage is .2 volt or more, problem is intermittent (not current).
  3. Turn ignition off. Inspect ECT and harness connector terminals. If no problem is found, go to next step. If problem is found, repair as necessary and go to step  7 .
  4. Turn ignition on. Using scan tool, access PID/DATA MONITOR. Record PID data for ECT V. If ECT voltage is less than .2 volt, go to next step. If ECT voltage is .2 volt or more, replace ETS sensor. Go to step  7 .
  5. Turn ignition off. Disconnect PCM connector. Check continuity between ECT sensor harness connector terminal "A" (Violet/Yellow wire) and ground. If continuity is not present, go to next step. If continuity is present, repair short to ground on Violet/Yellow wire. Go to step  7 .
  6. Check continuity between ECT harness connector terminals "A" (Violet/Yellow wire) and "B" (Orange wire). If continuity is not present, go to next step. If continuity is present, repair short between circuits as necessary and go to next step.
  7. Reconnect all connectors. Turn ignition on. Clear DTC from memory. Start engine. Recheck for DTCs. If same DTC is not present, go to next step. If same DTC is present, replace PCM. Go to next step.
  8. Clear DTC from memory. Recheck for DTCs. If any DTC is present, diagnose and repair DTC. If no DTCs are present, test is complete.
scientia non olet · About LEMON Manuals