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:

    Child restraint system fixed with an ISOFIX lower anchorage (for Puerto Rico)
    ■ ISOFIX lower anchorages (ISOFIX child restraint system) Lower anchorages are provided for the outboard rear seats. (Marks displaying the location of the anchorages are attached to the seats.) ■ When installing in the rear outboard seats Install the child restraint system in accordance to the ...

    Manual air conditioning system∗
    Air conditioning controls ► Heater ► Air conditioning system ■ Adjusting the temperature setting ► Heater To adjust the temperature setting, turn the dial clockwise to increase the temperature. ► Air conditioning system To adjust the temperature setting, tu ...

    Inspection procedure
    1 Check front airbag sensor (rh) circuit (to b+)(airbag sensor assy center – airbag front rh sensor) Disconnect the negative (–) terminal cable from the battery, and wait at least for 90 seconds.  disconnect the connectors between the airbag front rh sensor and the airbag sen ...