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:
Brake
On–vehicle inspection
1. Inspect brake line pipes and hoses
Hint:
work in a well–lighted area. Turn the front wheels fully to the
right or left before begining.
check all the brake lines and hoses for:
damage
wear
deformation
cracks
corrosion
leaks
bends
twi ...
Engine mechanical
Preparation
Sst
Recomended tools
Ssm
Equipment
Exhaust
Preparation
Equipment
...
Diagnostic trouble code chart
The inspection procedures are shown in the table below. This table allows
efficient and accurate troubleshooting
using the diagnostic trouble codes displayed in the diagnostic trouble code
chart. Proceed with
troubleshooting in accordance with the inspection procedures listed in the
diagnost ...


