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
    1. Remove engine under cover rh 2. Remove fan and generator v belt 3. Remove generator assy Disconnect the wire clamp from the wire clip on the rectifire end frame.  remove the rubber cap and nut, and disconnect the alternator wire.  disconnect the alternator connecto ...

    On–vehicle inspection
    1. Inspect brake booster Airtightness check.  Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly. Hint: if the pedal goes down farthest at the 1st time, but gradually rises after the 2nd or 3rd time, the booster is airtight. ...

    Using a top tether anchorage (for Puerto Rico)
    ■ Top tether anchorages Top tether anchorages are provided for each rear seat. Use top tether anchorages when fixing the top strap. Top tether anchorages Top strap ■ Fixing the top strap to the top tether anchorages Install the child restraint system in accordance to the operation manual e ...