Circuit Description

WARNING: This page is about a different car, the 2003 Toyota Matrix and 2003 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Bank No. 1 refers to bank that includes cylinder No. 1.
Sensor No. 2 refers to sensor being farther from engine body.

For circuit description, see DTC P0125: INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL . Detecting conditions of DTCs are:

When heater operates, heater current exceeds 2 A (2 trip detection logic).
When heater operates, heater current is 0.2 A or less (2 trip detection logic).