Toyota Celica 2005 Repair Manual page 588

DTC P0116
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI−382.
DTC No.
The engine coolant temperature is 35°C (95°F) or more but
less than 60°C (140°F) when the engine is started, and condi-
tions (a) and (b) are met:
(a) Vehicle has accelerated and decelerated.
(b) Engine coolant temperature remains within 3°C (5.4°F) of
the initial engine coolant temperature (2 trip detection logic)
P0116
S The engine coolant temperature is more than 60°C (140°F)
when the engine is started and the vehicle has accelerated
and decelerated
S The engine coolant temperature sensor records a tempera-
ture variation of below 1°C (1.8°F) successively 6 times (6
trip detection logic)
MONITOR DESCRIPTION
The ECT (Engine Coolant Temperature) sensor is used to monitor the engine coolant temperature. The ECT
sensor has a thermistor that varies its resistance depending on the temperature of the engine coolant. When
the coolant temperature is low, the resistance in the thermistor increases. When the temperature is high, the
resistance drops. The variations in resistance are reflected in the voltage output from the sensor. The ECM
monitors the sensor voltage and uses this value to calculate the engine coolant temperature. When the sen-
sor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT
sensor and sets a DTC.
Examples:
(1) Upon starting the engine, the ECT is between 35°C (95°F) and 60°C (140°F). If, after driving for 250
sec., the ECT still remains within 3°C (5.4°F) of the starting temperature, a DTC will be set (2 trip detection
logic).
(2) Upon starting the engine, the ECT is over 60°C (140°F). If, after driving for 250 sec., the ECT still remains
within 1°C (1.8°F) of the starting temperature, a DTC will be set (6 trip detection logic).
MONITOR STRATEGY
Related DTCs
Required sensors/components
Required sensors/components
Frequency of operation
Duration
MIL operation
Sequence of operation
2005 CELICA (RM1131U)
DIAGNOSTICS
Engine Coolant Temperature Circuit Range/
Performance Problem
DTC Detecting Condition
Main sensors/components
Related sensors/components
Continuous
250 sec.
2 driving cycles (When temperature is fixed between 35_C (95_F) and 60_C (140_F))
6 driving cycles (When temperature is fixed at 60_C (140_F) or more)
None
− ENGINE (2ZZ−GE)
S Engine coolant temperature sensor
P0116
587
Trouble Area
Engine coolant temperature sensor range check
(Stuck)
Engine coolant temperature sensor
Intake air temperature sensor, Crankshaft posi-
tion sensor, Mass air flow meter
DI−389
DI381−14