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:
Unlocking and locking the doors from the inside
◆ Door lock switches
1 Locks all the doors
2 Unlocks all the doors
◆ Inside lock buttons
1 Locks the door
2 Unlocks the door
The front doors can be opened by pulling the inside handle even if the lock buttons
are in the lock position.
...
Basic inspection
When the malfunction is not confirmed in the dtc check, troubleshooting
should be carried out in all the
possible circuits considered as causes of the problem. In many cases, by
carrying out the basic engine check
shown in the following flowchart, the location causing the problem can be found ...
Inspection procedure
1 Inspect terminal voltage(od – body ground)
Disconnect the cruise control ecu connector.
turn the ignition switch to the on position.
measure the voltage between terminal od of cruise control
ecu and body ground.
Standard:
2 Inspect terminal voltage(od1 – bod ...


