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.
Problem symptoms table (2005/11-2006/01)
Hint:
Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms are
listed in order of probability in the "suspected area" column of
the table. Check each symptom by checking the suspected
areas in the order they are listed. Replace p ...
Inspection
Inspect cylinder block for warpage
Using a precision straightedge and feeler gauge,
measure the warpage of the surface that is in
contact with the cylinder head gasket.
Maximum warpage:
0.05 Mm (0.0020 In.)
If the warpage is greater than the maximum, replace
the cylinder block ...
On-vehicle inspection
Check accelerator pedal rod
Check the voltage.
Connect the intelligent tester to the dlc3.
Turn the ignition switch on
Turn the intelligent tester on.
Select the menu items: diagnosis /
enhanced obd ii / data list / all /
accel pos #1, accel pos #2.
Operate the acceler ...