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Home >> Mazda >> 2002 >> Protege5 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0117: Engine Coolant Temperature Sensor Circuit, Low Input >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Turn ignition off. Connect scan tool to DLC-2. Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step  6.
  2. 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  6.
  3. Measure resistance between ECT sensor terminals. If resistance is 111-25,403 ohms, go to next step. If resistance is not as specified, replace ECT sensor and go to step  6.
  4. Turn ignition switch off. Disconnect PCM 104-pin harness 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 between ECT sensor harness connector and PCM 104-pin harness connector terminal No. 38. See WIRING DIAGRAMS article. Go to step  6.
  5. Check continuity between ECT sensor harness connector terminals. If continuity is not present, go to next step. If continuity is present, repair short between circuits as necessary and go to next step.
  6. Reconnect all connectors. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Start engine. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P0117 is present, replace PCM and go to next step. If DTC P0117 is not present, go to next step.
  7. Cycle ignition switch from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.
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