Toyota Corolla Repair Manual: 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):
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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.
Coolant thermostat (coolant
temperature below thermostat
regulating temperature)
Dtc p0128 coolant thermostat (coolant
temperature below thermostat
regulating temperature)
Hint:
this is the purpose of the ”thermostat” malfunction detection. ...
Inspection procedure
Hint:
read freeze frame data using the hand-held tester or the obd ii scan tool.
Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, it is
usefu ...
Other materials:
Problem symptoms table
When the malfunction code is not confirmed in the diagnostic trouble code
check and the problem still can
not be confirmed in the basic inspection, proceed to this problem symptoms
tables and troubleshoot according
to the numbered order given below.
*: A/t only ...
Inspection procedure
Hint:
perform the troubleshooting of dtc p0335 first. If no trouble is
found, troubleshoot the engine mechanical
systems.
Read freeze frame data using the hand-held tester or the obd ii scan tool.
Freeze frame data records
the engine conditions when a malfunction is detected. When tr ...
Diagnostic trouble code chart
If a dtc is displayed during the dtc check, check the circuit listed in the
table below and proceed to the
page given.
* :● ... Mil light up
...
