Description
A thermistor, whose resistance value varies according to the ect, is built into the engine coolant temperature (ect) sensor.
The structure of the sensor and its connection to the ecm are the same as those of the intake air temperature (iat) sensor.
Hint:
When any of dtcs p0115, p0117 and p0118 are set, the ecm enters fail-safe mode. During fail-safe mode, the ect is estimated to be 80°c (176°f) by the ecm. Fail-safe mode continues until a pass condition is detected.
Hint:
When any of these dtcs are set, check the ect by selecting the following menu items on the intelligent tester: diagnosis / enhanced obd ii / data list / primary / coolant temp.
Monitor description
The engine coolant temperature (ect) sensor is used to monitor the ect. The ect sensor has a thermistor with a resistance that varies according to 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. These variations in resistance are reflected in the output voltage from the sensor. The ecm monitors the sensor voltage and uses this value to calculate the ect. 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: if the sensor output voltage is more than 4.91 V for 0.5 Seconds or more, the ecm determines that there is an open in the ect sensor circuit, and sets dtc p0118. Conversely, if the voltage output is less than 0.14 V for 0.5 Seconds or more, the ecm determines that there is a short in the sensor circuit, and sets dtc p0117.
If the malfunction is not repaired successfully, a dtc is set 0.5 Seconds after the engine is next started.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Component operating range
Wiring diagram
Inspection procedure
Hint:
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.
Standard value: between 80°c and 100°c (167°f and 212°f) with warm engine.
Result
Hint:
Standard value: 140°c (284°f) or higher.
Standard resistance
Good connection to ecm. If ok, replace ecm
Standard value: -40°c (-40°f)
Standard resistance
Fuel information
You must only use unleaded gasoline in your vehicle.
Select octane rating 87 (research octane number 91) or higher.
Use of unleaded gasoline with an octane rating lower than 87
may result in engine knocking. Persistent knocking can lead to
engine damage.
At minimum, the gasoline you use sho ...
Disassembly
Caution:
Wear protective gloves. Sharp areas on the seat frame
(with adjuster) may injure your hands.
Hint:
Use the same procedures for the rh side and lh side.
The procedures listed below are for the lh side.
Remove vertical adjuster cover lh (for driver side)
Using a screw ...
Security indicator light circuit
Description
When the transponder key is registered, the transponder key ecu indicates the
key registration condition
by lighting up, blinking or turning off the security indicator.
Wiring diagram
Inspection procedure
Perform active test by intelligent tester (security indicator light)
...