Toyota RAV4 (XA40) 2013-2018 Service Manual: Coolant thermostat (coolant temperature below thermostat regulating temperature)
Hint:
This dtc relates to the thermostat.
Description
This dtc is set when the engine coolant temperature (ect) does not reach 75°c (167°f) despite sufficient engine warm-up time having elapsed.
Monitor description
The ecm estimates the ect based on the starting temperature, engine loads, and engine speeds. The ecm then compares the estimated temperature with the actual ect. When the estimated ect reaches 75°c (167°f), the ecm checks the actual ect. If the actual ect is less than 75°c (167°f), the ecm interprets this as a malfunction in the thermostat or the engine cooling system and sets the dtc.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
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.
- Check any other dtcs output (in addition to dtc p0128)
- Connect the intelligent tester to the dlc3.
- Turn the ignition switch on.
- Turn the tester on.
- Select the following menu items: diagnosis / enhanced obd ii / dtc info / current codes.
- Read dtcs.
Hint:
If any dtcs other than p0128 are output, troubleshoot those dtcs first.
- Check cooling system
- Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modifications.
- Inspect thermostat
- Remove the thermostat (see page co-15).
- Measure the valve opening temperature of the thermostat.
Standard value: 80 to 84°c (176 to 183°f)
Hint:
In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.
- Reinstall the thermostat (see page co-15).
Insufficient coolant temperature for closed loop fuel control
Description
Refer to dtc p0115 (see page es-105).
Monitor description
The resistance of the ect sensor varies in proportion to the actual ect. The
ect supplies a constant
voltage to the ...
Oxygen sensor circuit
Description
In order to obtain a high purification rate of the carbon monoxide (co),
hydrocarbon (hc) and nitrogen
oxide (nox) components in the exhaust gas, a twc is used. For the most effici ...
Other materials:
Reassembly
Install front oil pump oil seal
Using sst and a hammer, install a new oil seal to
the pump.
Sst 09350-32014 (09351-32140)
Hint:
The seal end should be flat with the outer edge of
the oil pump.
Coat the lip of the oil seal with petroleum jelly.
Install front oil pump bo ...
Unlock warning switch
Inspection
Inspect unlock warning switch assembly
Measure the resistance of the switch.
Standard resistance
If the result is not as specified, replace the switch
assembly.
Ecu power source circuit
Description
This circuit provides power to operate the transponder key ecu.
Wir ...
Shifting the shift lever
Vehicles without a smart key system
While the engine switch is in the
“on” position, move the shift
lever with the brake pedal depressed.
When shifting the shift lever between p and d, make sure that the
vehicle is completely stopped.
Vehicles with a smart key system
While the en ...
