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:
Replacement
1. Remove console box sub–assy rear
2. Remove parking brake lever sub–assy
3. Remove exhaust pipe assy front
4. Remove front floor heat insulator no.1
Remove the 3 nuts and front floor insulator no.1.
5. Remove front floor heat insulator no.2
Remove the 2 nuts and front ...
Oil filter sub–assy
Replacement
Caution:
prolonged and repeated contact with mineral oil will result in the
removal of natural fats from
the skin, leading to dryness, irritation and dermatitis. In addition, used
engine oil contains potentially
harmful contaminants which may cause skin cancer.
Exercise ...
Inspection procedure
Hint:
hand–held tester only:
narrowing down the trouble area is possible by performing ”a/f control” active
test (heated oxygen
sensor or other trouble areas can be distinguished). Perform active test using
hand–held tester (a/f
control).
Perform active test using the hand–held ...


