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.
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Dtc no |
Dtc detection condition |
Trouble area |
| P0128 | Condition (a), (b) and (c):
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Monitor description

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 malfunction thresholds

Component operating range

Monitor result (mode 06 data)

Refer to page 05–27 for the detailed information on checking monitor status.
Other materials:
Foamed material application areas
If an increase in temperature or other condition damages the foamed material
when repairing or replacing the panel,
fill in the insufficient areas with urethane foam. The following illustration
shows the areas for one side, but the
foamed material must be applied equally to both the left and r ...
Tire pressure warning system (if equipped)
Your vehicle is equipped with a tire pressure warning system that uses tire pressure
warning valves and transmitters to detect low tire inflation pressure before serious
problems arise.
◆ Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire press ...
Symptom confirmation and diagnostic trouble code
Hint:
the diagnostic system in corolla has various functions. The first
function is the diagnostic trouble
code (dtc) check, in which a malfunction in the signal circuits to the ecu
is stored in code form in
the ecu memory. Another function is the input signal check, which checks if
...


