A25A-FKS (ENGINE CONTROL): SFI SYSTEM: P012800,P012807; Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature); 2021 MY RAV4 RAV4 HV [08/2020

The ECM uses the engine coolant temperature sensor, installed to the water outlet, to monitor the operation of the thermostat.

*1: w/ Grille Shutter System
*2: w/o Grille Shutter System

MONITOR DESCRIPTION

P012800: Judgment by Simulated Engine Coolant Temperature

The ECM estimates the engine coolant temperature based on the starting temperature, engine loads, and engine speeds. The ECM then compares the estimated temperature with the actual engine coolant temperature. When the estimated engine coolant temperature reaches 75°C (167°F), the ECM checks the actual engine coolant temperature. If the actual engine coolant temperature is less than 75°C (167°F), the ECM interprets this as a malfunction in the thermostat or the engine cooling system and stores the DTC.

P012807: Judgment by Engine Coolant Temperature and No. 2 Engine Coolant Temperature Changes (w/ Grille Shutter System)

When the engine coolant temperature is less than 75°C (167°F) and the water inlet housing with water pump sub-assembly is operating, if the rate of change and detected temperature of the engine coolant temperature sensor and No. 2 engine coolant temperature sensor differ by less than 0.1°C/sec. and 6.6°C respectively for a certain amount of time, the ECM will determine that the thermostat is stuck open, illuminate the MIL and store a DTC.

P012807: Judgment by Engine Coolant Temperature Change at High Vehicle Speed (w/o Grille Shutter System)

When the vehicle is being driven between 65 and 128 km/h (40.625 and 80 mph) and the monitoring conditions are met, the change in engine coolant temperature is monitored. The amount of change is judged to be normal or abnormal every 13 seconds, in order to monitor the thermostat operation. If the engine coolant temperature changes more than the threshold, the thermostat is judged as normal, but if it changes less than the threshold, the thermostat is judged to be malfunctioning. If an abnormal judgment is made 3 times, the ECM will illuminate the MIL and store a DTC.

MONITOR STRATEGY

w/ Grille Shutter System

w/o Grille Shutter System

TYPICAL ENABLING CONDITIONS

ALL

Judgment by Simulated Engine Coolant Temperature

Judgment by Engine Coolant Temperature and No. 2 Engine Coolant Temperature Changes (w/ Grille Shutter System)

Judgment by Engine Coolant Temperature Change at High Vehicle Speed (w/o Grille Shutter System)

TYPICAL MALFUNCTION THRESHOLDS

P012800: Judgment by Simulated Engine Coolant Temperature

Judgment by Engine Coolant Temperature and No. 2 Engine Coolant Temperature Changes (w/ Grille Shutter System)

P012807: Judgment by Engine Coolant Temperature Change at High Vehicle Speed (w/o Grille Shutter System)

CONFIRMATION DRIVING PATTERN

Stop the engine and allow it to soak.
Connect the Techstream to the DLC3.
Turn the ignition switch to ON [A].
Turn the Techstream on.
Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature and Intake Air Temperature.
Check that the value of the Data List item Coolant Temperature is 56°C (133°F) or less and the value of the Data List item Intake Air Temperature is between 0 and 35°C (32 and 95°F).
Set the heater control to MAX HOT with fresh air mode selected and turn the A/C off.
Start the engine and drive the vehicle at 80 km/h (50 mph) or more for 20 minutes [B].
CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
After the value of the Data List item Coolant Temperature stabilizes, check that it is 75°C (167°F) or higher.
HINT:

If the value of the Data List item Coolant Temperature is less than 75°C (167°F) while driving the vehicle at 80 km/h (50 mph), inspect the cooling system and thermostat.
Enter the following menus: Powertrain / Engine / Trouble Codes [C].
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P012800 or P012807.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

HINT:

If the judgment result is NORMAL, the system is normal.
If the judgment result is ABNORMAL, the system has a malfunction.
If the judgment result is INCOMPLETE, If the judgment result is INCOMPLETE, perform steps [D] through [G].
[A] to [C]: Normal judgment procedure.
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
When clearing the permanent DTCs, do not disconnect the cable from the battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

With the engine stopped, leave the vehicle outside overnight [D].
Turn the ignition switch to ON [E].
Turn the Techstream on.
Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.
Check that the value of the Data List item Coolant Temperature is 25°C (77°F) or less.
Start the engine and drive the vehicle at 90 km/h (56 mph) or more for 20 minutes [F].
CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Enter the following menus: Powertrain / Engine / Trouble Codes [G].
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P012800 or P012807.

Check the DTC judgment result again.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

HINT:

If the judgment result is NORMAL, the system is normal.
If the judgment result is ABNORMAL, the system has a malfunction.
[D] to [G]: Normal judgment procedure.
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
When clearing the permanent DTCs, do not disconnect the cable from the battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

CAUTION / NOTICE / HINT

PROCEDURE

Powertrain > Engine > Trouble Codes

If any DTCs other than P012800 or P012807 are output, troubleshoot those DTCs first.

(a) Check for defects in the engine cooling system that might cause the system to be too cold, such as abnormal cooling fan operation or any modifications.

(a) Inspect the water inlet with thermostat sub-assembly (thermostat opening temperature).

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.

Powertrain > Transmission > Trouble Codes

If DTCs related to the ATF temperature are output, troubleshoot those DTCs first.

(e) Enter the following menus: Powertrain / Engine / Active Test / Activate the Coolant Water Route Switching Valve / Data List / Engine Speed and Coolant Water Route Switching Valve.

Powertrain > Engine > Active Test

(f) Perform the Active Test to close the flow shutting valve (for Heater Control).

(h) With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 1500 rpm for 15 seconds.

(i) During the engine warm-up process, touch the flow shutting valve (for Heater Control) outlet and inlet hoses and check if there is a difference in temperature.

(e) Enter the following menus: Powertrain / Engine / Active Test / Activate the Coolant Water Route Switching Valve 2 / Data List / Engine Speed and Coolant Water Route Switching Valve 2.

Powertrain > Engine > Active Test

(h) With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 1500 rpm for 15 seconds.

(i) During the engine warm-up process, touch the flow shutting valve (for ATF Control) outlet and inlet hoses and check if there is a difference in temperature.