
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 circuitManual air conditioning system
Air conditioning controls
Fan speed control switch
Temperature control switch
On/off switch
Windshield defogger switch
Rear window and outside rear view mirror defoggers* switch
Airflow mode control switch
Outside/recirculated air mode switch
"A/C" switch
"MAX A/C" switch
*: If equipped
...
If the vehicle battery
is discharged
The following procedures may be used to start the engine if the
vehicle’s battery is discharged.
You can also call your toyota dealer or a qualified repair shop.
If you have a set of jumper (or booster) cables and a second vehicle
with a 12-volt battery, you can jump start your vehicle by fo ...
Adjusting the mirrors
Make sure that you can see backward clearly by adjusting the inside
and outside rear view mirrors properly.
Caution
Observe the following precautions.
Failure to do so may result in death or serious injury.
Do not adjust the position of the driver’s seat while driving.
Doing so could ...