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.
|
Dtc no |
Dtc detection condition |
Trouble area |
| P0128 | Condition (a), (b) and (c):
|
|
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:
Instrument panel
Engine switch
Starting the engine/changing the positions*1
Starting the engine/changing the modes*2
Emergency stop of the engine
When the engine will not start
Warning messages
Shift lever
Changing the shift position
Precautions for towing
When the shift lever does not move
Meters
Read ...
Removal & installation and disassembly & reassembly
1. Remove oxygen sensor
Remove a clip and tear off the floor mat.
disconnect a oxygen sensor connector.
Remove the oxygen sensor.
2. Remove tail pipe assy
Remove 2 bolts, 2 springs and tail pipe assy.
3. Remove floor panel brace front
Remove 2 nuts and the ...
Hydraulic test
1. Perform hydraulic test
Measure the line pressure.
Notice:
Do the test at normal operation atf temperature 50 to 80 °c (122 to
176 °f).
The line pressure test should always be carried out in pairs. One
technician should observe
the conditions of wheels or wheel stopper outsi ...


