Toyota Tacoma manuals

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 failsafe 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
  • Open or short in engine coolant temperature sensor circuit
  • engine coolant temperature sensor
  • ecm
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 handheld tester or the obd ii scan tool.

Monitor description

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 enabling conditions

Typical malfunction thresholds

Typical malfunction thresholds

Component operating range

Component operating range

Wiring diagram

Wiring diagram

Inspection procedure

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:

Other functions
■  Switching between outside air and recirculated air modes Press . The mode switches between outside air mode (indicator off) and recirculated air mode (indicator on) each time is pressed. ■ Defogging the windshield Defoggers are used to defog the windshield and front side w ...

Inspection procedure
1 Inspect park/neutral position switch assy Disconnect the park/neutral position switch connector.  measure resistance according to the value(s) in the table below when the shift lever is moved to each position. Standard: 2 Check harness and connector(park/neutral position ...

Vehicle lift and support locations
1. Notice about vehicle condition when jacking up As a rule, the vehicle must be unloaded when jacking up. Never jack up or lift up the vehicle loaded with things of heavy weight.  when removing any parts of heavy weight like the engine and transmission, the center of gravity of ...

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