Diagnostic Aids

If DTCs P0106 and P0121 are also set, malfunction may be in sensor ground circuit. Check for proper operation of engine cooling system and coolant level. In cold weather when vehicle is started and sits while warming, a faulty thermostat that stays slightly open can cause this DTC to set. Check for a shifted ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article. Check for a poor PCM electrical connection.

An intermittent malfunction may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside insulation. Check harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, or poor terminal-to-wire connections before component replacement.