Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Coolant thermostat (coolant
temperature below thermostat
regulating temperature)
Toyota Corolla (E120): 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.
Other materials:
On–vehicle inspection
1. Inspect drive belt
Visually check the belt for excessive wear, frayed cords,
etc.
If any defect is found, replace the drive belt.
Hint:
cracks on the rib side of a belt are considered acceptable. If the
missing chunks from the ribs are found on the belt, it should be
replaced.
2 ...
Inspection procedure
1 Check courtesy lamp switch
Check the courtesy switch, as shown in the illustration
and table.
Standard:
2 Check wire harness (integration relay door courtesy sw)
Disconnect the integration relay and door courtesy connectors.
check the continuity between th ...
Circuit description
The intake air temperature (iat) sensor, mounted on the mass
air flow (maf) sensor, monitors the intake air temperature. The
iat sensor has a thermistor that varies its resistance depending
on the temperature of the intake air. When the air temperature
is low, the resistance in the thermisto ...