Toyota Corolla (E120): Circuit description

If the engine coolant temperature (ect) does not reach 75°c (167°f) despite sufficient warm – up time has elapsed.

Dtc no

Dtc detection condition

Trouble area

P0128 Condition (a), (b) and (c):
  1.  cold start
  2.  after engine is warmed up
  3.  engine coolant temperature is less than 75°c (167°f)
  • Thermostat
  • cooling system
  • engine coolant temperature sensor
  • ecm

Monitor description

The ecm estimates the engine coolant temperature (ect) based on starting

The ecm estimates the engine coolant temperature (ect) based on starting temperature, engine loads, and engine speeds. The ecm then compares the estimated ect with the actual ect. When the estimated ect reaches 75 c (167 f) the ecm checks the actual ect. If the actual ect is less than 75 c (167 f), the ecm will interpret this as a fault in the thermostat or engine cooling system or thermostat and set a dtc.

Monitor strategy

Typical enabling conditions

Typical enabling conditions

Typical malfunction thresholds

Typical malfunction thresholds

Component operating range

Component operating range

Monitor result (mode 06 data)

Monitor result (mode 06 data)

Refer to page 05–27 for the detailed information on checking monitor status.

Refer to page 05–27 for the detailed information on checking monitor status.

    Share this page:

    Other materials:

    Replacement
    Hint: installation is in the reverse order of the removal. But the installation is indicated only when it has a point. 1. Remove rear door opening trim rh 2. Remove rear door opening trim lh 3. Remove rear seat cushion assembly ( or 72–8) 4. Remove rear seat back assy (fixed type rear seat) ...

    Inspection procedure
    Hint: the switch described in this text is a switch for transmitting signals which is built in the door control transmitter. 1 Check wireless door lock control functions Normal 2 Replace transmitter battery with normal one After replacing the transmitter battery with a new or normal o ...

    Safe Exit Assist
    The safe exit assist is a system that uses rear side radar sensors installed on the inner side of the rear bumper to help occupants judge if an approaching vehicle or bicycle may collide with a door when opening it or cancel opening of the door, to reduce the possibility of a collision. WARNING ■C ...