
Hint:
This dtc relates to the thermostat.
Description
This dtc is set when the engine coolant temperature (ect) does not reach 75°c (167°f) despite sufficient engine warm-up time having elapsed.

Monitor description

The ecm estimates the ect based on the starting temperature, engine loads, and engine speeds. The ecm then compares the estimated temperature 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 interprets this as a malfunction in the thermostat or the engine cooling system and sets the dtc.
Monitor strategy
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Typical enabling conditions

Typical malfunction thresholds

Inspection procedure
Hint:
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

Hint:
If any dtcs other than p0128 are output, troubleshoot those dtcs first.


Standard value: 80 to 84°c (176 to 183°f)
Hint:
In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.

Insufficient coolant temperature for closed loop fuel control
Oxygen sensor circuitAutomatic
air conditioning system
Air outlets and fan speed are automatically adjusted according
to the temperature setting.
Driver’s side temperature control
dial
Automatic mode button
Micro dust and pollen filter
mode button
Driver’s side temperature setting
display
Fan speed display
Air outlet display ...
Registration
Hint:
The key has 2 codes: the key code (immobiliser code) and
the wireless code (recognition code). Both of these codes
need to be registered. For wireless code registration
procedures, refer to the following procedures (see page dl-
46). For key code registration procedures, refer to the
pro ...
Cleaning and protecting the vehicle interior
Perform cleaning in a manner
appropriate to each
component and its material.
Protecting the vehicle
interior
Remove dirt and dust using a
vacuum cleaner. Wipe dirty
surfaces with a cloth dampened
with lukewarm water.
If dirt cannot be removed,
wipe it off with a soft cloth
dampened with neut ...