
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
![]()

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 circuitIdentification information
Vehicle identification and serial numbers
Vehicle identification number
The vehicle identification number is stamped on the
vehicle identification number plate and on the
certification label, as shown in the illustrations.
Vehicle identification number plate
Certification label ...
Luggage compartment
features
Cargo hooks
Raise the hooks to use.
The cargo hooks are provided for
securing loose items.
Caution
When the cargo hooks are not in use
To avoid injury, always return the cargo hooks to their stowed
positions.
Grocery bag hooks
Notice
Grocery bag hook weight capacity
Do not hang ...
Before refueling the vehicle
Close all the doors and windows, and turn the engine switch to the
“lock” position (vehicles without a smart key system) or off (vehicles
with a smart key system).
Confirm the type of fuel.
Fuel types
Unleaded gasoline (octane rating 87 [research octane number 91] or
higher)
Cauti ...