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:
Control module communication bus off
Description
Inspection procedure
The skid control ecu inputs the signals from the ecm, steering angle sensor,
and yaw rate and
acceleration sensor via can communication system.
Check harness and connector (momentary interruption)
Using the data list of the intelligent test ...
Antenna coil open / short
Description
The transponder key coil receives key code signals from the transponder chip
in the key grip. The coil
built into the transponder key amplifier amplifies the key code signals and
outputs the signal to the
transponder key ecu.
Wiring diagram
Inspection procedure
R ...
Removal
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove fan and generator v belt
Remove the belt (see page em-6).
...
