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Home › Mitsubishi › 2002 › Montero Limited › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0118: Engine Coolant Temperature Circuit High Input › Test Procedure

Test Procedure

  1. Turn ignition on. Using scan tool, check data list item No. 21 (engine coolant temperature sensor). If scan tool value approximately matches engine coolant temperature, problem is intermittent. For trouble shooting, see INTERMITTENT DIAGNOSTIC TROUBLE CODES . If scan tool value does not match engine coolant temperature, go to next step.
  2. Turn ignition off. Disconnect ECT sensor connector. See Figure. Check ECT sensor connector for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step  11. If problem does not exist, go to next step.
  3. Turn ignition on. Measure voltage between ground and ECT sensor connector terminal No. 1 (Yellow/Green wire). Voltage should be 4.8-4.9 volts. If voltage is as specified, go to step  7. If voltage is not as specified, go to next step.
  4. Measure voltage between ground and PCM connector D-108 terminal No. 44 (Yellow/Green wire) by backprobing. Voltage should be 4.8-5.2 volts. If voltage is as specified, go to next step. If voltage is not as specified, go to step  6.
  5. Turn ignition off. Check PCM connector D-108 for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step  11. If problem does not exist, repair Yellow/Green wire between PCM connector D-108 terminal No. 44 and ECT sensor connector terminal No. 1. Go to step  11.
  6. Check PCM connector D-108 for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step  11. If problem does not exist, replace PCM. Go to step  11.
  7. Check for continuity between ground and ECT sensor connector terminal No. 2 (Black wire). If continuity exists, go to step  10. If continuity does not exist, go to next step.
  8. Check PCM connector D-108 for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step  11. If problem does not exist, go to next step.
  9. Check continuity between ECT sensor connector terminal No. 2 (Black wire) and PCM connector D-108 terminal No. 57. If continuity exists, replace PCM. Go to step  11. If continuity does not exist, repair Black wire between ECT sensor connector terminal No. 2 and PCM connector D-108 terminal No. 57. Then go to step  11.
  10. Remove ECT sensor. Immerse sensor portion of ECT sensor in hot water and check resistance between ECT sensor connector terminals. Compare resistance with expected value. See ECT SENSOR RESISTANCES . If resistance is as specified, replace PCM. Go to next step. If resistance is not as specified, replace ECT sensor. Go to next step.
    NOTE: To install ECT sensor, apply thread sealer to ECT sensor threads and tighten ECT sensor to 15-29 ft. lbs. (19-39 N.m).
  11. Test drive vehicle following OBD-II drive cycle Other Monitor pattern. See OTHER MONITOR  under OBD-II DRIVE CYCLES under VERIFYING REPAIRS. Check for DTCs. If DTC P0118 is output, go to  1 and retry diagnostic procedure. If DTC P0118 is not output, inspection is complete.
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