A25A-FXS (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, and the No. 2 engine coolant temperature sensor*1, installed to the radiator pipe assembly, 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 load, and engine speed. 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 of the thermostat or in the engine cooling system, illuminates the MIL and stores this 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 15 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

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)

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.
Put the engine in Inspection Mode (Maintenance Mode).
Click here
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 auxiliary 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.
Put the engine in Inspection Mode (Maintenance Mode).
Click here
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 auxiliary 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

NOTICE:

Vehicle Control History may be stored in the hybrid vehicle control ECU assembly if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the Freeze Frame Data and Vehicle Control History can be useful for troubleshooting.
for AWD with NICKEL METAL HYDRIDE BATTERY

Click here

for LITHIUM-ION BATTERY

Click here

(Select Powertrain in Health Check and then check the time stamp data.)

Click here
If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU assembly, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.
for AWD with NICKEL METAL HYDRIDE BATTERY

Click here

for LITHIUM-ION BATTERY

Click here

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.