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Home >> Toyota >> 2004 >> Matrix Base, FWD, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 137 (Engine Control System Self Diagnostics (2UZ-FE)) >> Diagnostic Tests >> DTC P0116: Engine Coolant Temperature Sensor Circuit Range/Performance Problem & DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
  1. Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTCs P0116 and/or P0125 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
  2. Remove and inspect cooling system thermostat for damage and proper operation. Thermostat is located behind thermostat housing on driver's side front of engine, just behind cooling fan. If thermostat is defective, replace thermostat. If thermostat is okay, replace ECT sensor. ECT sensor is located behind upper timing belt cover, on top of intake manifold and contains Black 2-pin electrical connector with Brown and Red/Blue wires.
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