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.
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Dtc no |
Dtc detection condition |
Trouble area |
| P0128 | Condition (a), (b) and (c):
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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:
Circuit description
The park/neutral position switch detects the shift lever position and sends
signals to the ecm.
Monitor description
The park/neutral position switch detects the gearshift position and sends a
signal to the ecm.
For security, the park/neutral position switch detects the gearshift positio ...
Windshield wiper switch assy
Replacement
1. Remove steering column cover lwr
Remove 3 screws and steering column cover lwr.
2. Remove windshield wiper switch assy
Disconnect the connecter of the windshield wiper switch.
release the claw and pull out the windshield wiper switch
assy as shown in the ...
Check mode procedure
Hint:
hand–held tester only:
compared to the normal mode, the check mode has more sensing
ability to detect malfunctions. Furthermore, the same diagnostic
items which are detected in the normal mode can also be
detected in the check mode.
1. Check mode procedure(using the hand–held tester) ...


