Toyota Corolla Repair Manual: Circuit description
A thermistor is built in the engine coolant temperature sensor and changes the resistance value according to the engine coolant temperature.
The structure of the sensor and connection to the ecm is the same as those of the intake air temperature sensor.
Hint
: if the ecm detects the dtc p0115, p0117 or p0118, it operates the fail–safe function in which the engine coolant temperature is assumed to be 80 c (176 °F).
|
Dtc no. |
Proceed to |
Dtc detection condition |
Trouble area |
| P0115 | Step 1 | Open or short in engine coolant temperature sensor circuit for 0.5 Seconds |
|
| P0117 | Step 4 | Short in engine coolant temperature sensor circuit for 0.5 Seconds | |
| P0118 | Step 2 | Open in engine coolant temperature sensor circuit for 0.5 Seconds |
Hint
: after confirming dtc p0115, p0117 or p0118, confirm the engine coolant temperature in the ”diagnosis/ enhanced obd ii/data list/all” using the hand–held tester or the obd ii scan tool.
Monitor description
The engine coolant temperature (ect) 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 sensor output voltage deviates from the normal operating range, the ecm interprets this as a fault in the ect sensor and sets a dtc.
Example: when the ecm calculates that the ect is –40 c (–40 °F), or more than 140 c (284 °F), and if either the condition continues for 0.5 Sec or more, the ecm will set a dtc.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Component operating range
Wiring diagram
Engine coolant temperature circuit
Dtc p0115 engine coolant temperature circuit
Dtc p0117 engine coolant temperature circuit
low input
Dtc p0118 engine coolant temperature circuit
high input ...
Inspection procedure
Hint:
if different dtcs related to different systems that have terminal e2
as the ground terminal are output
simultaneously, terminal e2 may be open.
Read freeze frame data using the hand-h ...
Other materials:
Communication system
Horn system
Location
Problem symptoms table
Inspection
1. Inspect low pitched horn assy
Connect the positive (+) lead from the battery to the terminal
and the negative (–) lead to the horn body, and check
that the horn blows.
If the result is not as specified, replace the ho ...
Overhaul
1. Remove repair service starter kit
Remove the nut, then disconnect the lead wire from terminal
c.
Remove the 2 screws which are used to secure the repair
service starter kit to the starter drive housing.
remove the repair service starter kit.
remove the return ...
Fog light switch
The fog lights secure excellent visibility in difficult driving conditions,
such as in rain and fog.
1 Turns the front fog lights off
2 Turns the front fog lights on
*1: For U.S.A.
*2: For Canada
■Fog lights can be used when
The headlights are on in low beam. ...