Cooling System [02/2019 - ]: Procedure

WARNING: This page is about a different variant/trim than selected.

CHECK VEHICLE CONDITION

Make sure that the front side of the radiator grille is not blocked with anything.

Ask the customer if the front side of the radiator grille was blocked with anything.

Result

Result	Proceed to
Not blocked.	A
Is/was blocked.	B

HINT:

If the radiator grille is blocked, the inverter coolant temperature will increase and this DTC may be stored.

Result:

IF EQUIPPED, EXPLAIN TO CUSTOMER THAT OPTIONAL COMPONENTS WILL BE REMOVED

Result:

See step 2

CHECK QUANTITY OF HV COOLANT

Check the HV coolant level in the inverter reserve tank.

Check for HV coolant leaks.

Result

Result	Proceed to
No leaks are found and the HV coolant level in the inverter reserve tank assembly is above the low line.	A
No leaks are found and the HV coolant level in the inverter reserve tank assembly is below the low line.	B
HV coolant leaks are evident.	C

HINT:

After repairing the HV coolant leaks and adding coolant, perform the Active Tests "Activate the Inverter Water Pump" (Hybrid Control System) and "Control the Cooling Fan Duty Ratio" (Engine Control System) and make sure that there are no malfunctions.
If there are signs of coolant leakage around the connecting parts of a hose and the inverter with converter assembly, replace the hose with a new one.

Result:

ADD HV COOLANT

Result:

INSPECT FOR COOLANT LEAK AND ADD COOLANT

Result:

See step 3

CHECK COOLANT HOSE

Check that the cooling system hoses are not kinked or clogged.

The cooling system hoses are not kinked or clogged.

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE COOLANT HOSE

Result:

See step 4

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE ENGINE COOLING FAN DUTY RATIO)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.

Enter the following menus: Powertrain / Engine / Active Test / Control the Engine Cooling Fan Duty Ratio.

Powertrain > Engine > Active Test

Tester Display
Control the Engine Cooling Fan Duty Ratio

Perform the "Control the Engine Cooling Fan Duty Ratio" Active Test.

Techstream Operation	Fan Operation
30 - 100%	Cooling fan operates
0%	Cooling fan stops

Result

Result	Proceed to
Cooling fan operate	A
Cooling fan does not operate	B
Cooling fan do not stop	B

Turn the ignition switch off.

Result:

CHECK COOLING FAN SYSTEM

Refer to Cooling Fan Circuit [02/2019 - 08/2020] , or refer to Cooling Fan Circuit [08/2020 - 12/2021] , or refer to Cooling Fan Circuit [12/2021 - ]

Result:

See step 5

PERFORM ACTIVE TEST USING TECHSTREAM (GRILLE SHUTTER OPERATION)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Enter the following menus: Body Electrical / Grille Shutter / Utility / Grille Shutter Control Mode Switching.

According to the display on the Techstream, change the grille shutter control mode from normal mode to maintenance mode.

Body Electrical > Grille Shutter > Utility

Tester Display
Grille Shutter Control Mode Switching

Enter the following menus: Body Electrical / Grille Shutter / Active Test / Shutter Closing Operation Lock Detection / Data List / Shutter Operation Lock Detection Result for Active Test.

According to the display on the Techstream, perform the Active Test and read the value of Data List item Shutter Operation Lock Detection Result for Active Test.

Body Electrical > Grille Shutter > Active Test

Active Test Display
Shutter Closing Operation Lock Detection

Data List Display
Shutter Operation Lock Detection Result for Active Test

"Normal" is displayed.

Enter the following menus: Body Electrical / Grille Shutter / Active Test / Shutter Opening Operation Lock Detection / Data List / Shutter Operation Lock Detection Result for Active Test.

According to the display on the Techstream, perform the Active Test and read the value of Data List item Shutter Operation Lock Detection Result for Active Test.

Body Electrical > Grille Shutter > Active Test

Active Test Display
Shutter Opening Operation Lock Detection

Data List Display
Shutter Operation Lock Detection Result for Active Test

"Normal" is displayed.

HINT:

When the value of Data List item Shutter Operation Lock Detection Result for Active Test is "Normal", it can be determined that the grille shutter system is normal.

Enter the following menus: Body Electrical / Grille Shutter / Utility / Grille Shutter Control Mode Switching.

According to the display on the Techstream, change the grille shutter control mode from maintenance mode to normal mode.

Body Electrical > Grille Shutter > Utility

Tester Display
Grille Shutter Control Mode Switching

Turn the ignition switch off.

Result

Proceed to
OK
NG

Result:

CHECK GRILLE SHUTTER SYSTEM

Refer to HOW TO PROCEED WITH TROUBLESHOOTING [02/2019 - 12/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2021 - ]

Result:

See step 6

PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE INVERTER WATER PUMP)

NOTE:

Make sure that the HV coolant level is above the low line of the inverter reserve tank.
Be sure to perform the inspection with the auxiliary battery voltage at 12 V or more.

HINT:

When the auxiliary battery voltage is low, the inverter water pump assembly may not operate.

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.

Enter the following menus: Powertrain / Hybrid Control / Active Test / Activate the Inverter Water Pump.

Powertrain > Hybrid Control > Active Test

Active Test Display
Activate the Inverter Water Pump

Data List Display
Inverter Water Pump Revolution

Select the Data List item "Inverter Water Pump Revolution".

According to the display on the Techstream, perform the Active Test "Activate the Inverter Water Pump" and check the value of the Data List item "Inverter Water Pump Revolution".

Tester Display	Condition	Specified Condition
Inverter Water Pump Revolution	Ignition switch ON During Active Test	3176 to 8617 rpm

HINT:

Perform the Active Test with the inverter coolant temperature between -15 and 65°C (5 to 149°F).
When the inverter water pump assembly is not operating, the Data List item "Inverter Water Pump Revolution" displays a value 200 rpm or less.

Turn the ignition switch off.

Result

Proceed to
OK
NG

Result:

See step 9

Result:

See step 7

READ VALUE USING TECHSTREAM (DATA LIST)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON (READY) and wait for 1 minute with the engine stopped.

Enter the following menus: Powertrain / Hybrid Control / Data List / Generator Inverter Calculated Temperature, Motor Inverter Temperature, Rear Motor Inverter Temperature, Boosting Converter Temperature (Upper), Boosting Converter Temperature (Lower) and Inverter Coolant Water Temperature.

Powertrain > Hybrid Control > Data List

Tester Display
Generator Inverter Calculated Temperature
Motor Inverter Temperature
Rear Motor Inverter Temperature
Boosting Converter Temperature (Upper)
Boosting Converter Temperature (Lower)
Inverter Coolant Water Temperature

Read the Data List with the engine stopped.

Result

Result	Proceed to
Other than below.	A
"Inverter Coolant Water Temperature" value is higher than the displayed temperature of any other Data List item by 20°C (68°F) or more.	B

HINT:

The lower limit temperature that can be displayed for "Generator Inverter Calculated Temperature", "Motor Inverter Temperature", "Boosting Converter Temperature (Upper)" and "Boosting Converter Temperature (Lower)" is 0°C (32°F). The lower limit temperature for "Inverter Coolant Water Temperature" is -40°C (-40°F). The "Inverter Coolant Water Temperature" value displayed on the Techstream may be lower than the others, but this is not a malfunction.

Turn the ignition switch off.

Result:

REPLACE INVERTER WITH CONVERTER ASSEMBLY

Refer to REMOVAL [02/2019 - 10/2019] , or refer to REMOVAL [10/2019 - 06/2020] , or refer to REMOVAL [06/2020 - 08/2020] , or refer to REMOVAL [08/2020 - 12/2021] , or refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

Result:

See step 8

CHECK HV COOLANT (CHECK FOR CONDITIONS THAT MAY HAVE CAUSED FREEZING)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.
Powertrain > Hybrid Control > Trouble Codes
Read the freeze frame data item "Ambient Temperature" using the Techstream.

Check if the freeze frame data item "Ambient Temperature" is below the freezing temperature of the HV coolant.

Result

Result	Proceed to
Ambient Temperature value is above freezing temperature of the HV coolant.	A
Ambient Temperature value is below freezing temperature of the HV coolant.	B

HINT:

HV coolant (SLLC) with a 30% concentration freezes at -15°C (5°F) and HV coolant (SLLC) with a 50% concentration freezes at -35°C (-31°F).
If the HV coolant freezes in the HV radiator or inverter water pump, the coolant temperature in the inverter with converter assembly rises because the HV coolant cannot circulate. As a result, a DTC may be stored.
A DTC is stored when the inverter water pump impeller cannot rotate due to freezing of the HV coolant.
If DTCs are output due to freezing of the LLC, the problem symptom cannot be reproduced. Check the LLC replacement history and whether the LLC was frozen based on the ambient temperature when the DTCs were stored.

Turn the ignition switch off.

Result:

COOLING SYSTEM NORMAL (PERFORM NEXT STEP FOR REFERENCED DTC)

Result:

REPLACE HV COOLANT

Refer to REPLACEMENT [11/2018 - 12/2021] , or refer to REPLACEMENT [12/2021 - ]

CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU ASSEMBLY CONNECTOR)
Refer to PROCEDURE - Step 1

Result

Proceed to

OK

NG

Result:

NG

CONNECT SECURELY

Result:

OK

See step 10

CHECK CONNECTOR CONNECTION CONDITION (INVERTER WATER PUMP ASSEMBLY CONNECTOR)

Check the connector connections and contact pressure of the relevant terminals for the inverter water pump assembly connector.

Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [11/2018 - ]

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The connector is connected securely, the terminals are not deformed or corroded and there are no contact problems.

Result

Proceed to
OK
NG

Result:

CONNECT SECURELY

Result:

See step 11

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - INVERTER WATER PUMP ASSEMBLY)

Disconnect the A29 hybrid vehicle control ECU assembly connector.
Disconnect the A53 inverter water pump assembly connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open)

Tester Connection	Condition	Specified Condition
A29-34 (IWP) - A53-3 (SWP)	Ignition switch off	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
A29-34 (IWP) or A53-3 (SWP) - Body ground and other terminals	Ignition switch off	10 kΩ or higher

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Front view of wire harness connector (to Hybrid Vehicle Control ECU Assembly)
*b	Front view of wire harness connector (to Inverter Water Pump Assembly)

Reconnect the A53 inverter water pump assembly connector.

Reconnect the A29 hybrid vehicle control ECU assembly connector.

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 12

READ VALUE USING TECHSTREAM (INVERTER WATER PUMP REVOLUTION)

NOTE:

Be sure to perform the inspection with the auxiliary battery voltage at 12 V or more.

HINT:

When the auxiliary battery voltage is low, the inverter water pump assembly may not operate.

Connect the Techstream to the DLC3.

Remove the INV W/P NO. 2 fuse from No. 1 engine room relay block and junction block assembly.

*1	No. 1 Engine Room Relay Block and Junction Block Assembly
*2	INV W/P NO. 2 Fuse

Turn the ignition switch to ON.

Enter the following menus: Powertrain / Hybrid Control / Data List / Inverter Water Pump Revolution.

Powertrain > Hybrid Control > Data List

Tester Display
Inverter Water Pump Revolution

According to the display on the Techstream, read the Data List.

Tester Display	Condition	Specified Condition
Inverter Water Pump Revolution	Ignition switch ON	200 rpm or less

Turn the ignition switch off.

Install the INV W/P NO. 2 fuse.

Result

Proceed to
OK
NG

Result:

REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY

Refer to REMOVAL [02/2019 - 10/2019] , or refer to REMOVAL [10/2019 - 08/2020] , or refer to REMOVAL [08/2020 - 12/2021] , or refer to REMOVAL [12/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023] , or refer to REMOVAL [10/2023 - ]

Result:

See step 13

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - INVERTER WATER PUMP ASSEMBLY)

Disconnect the A29 hybrid vehicle control ECU assembly connector.

Remove the INV W/P relay from No. 1 engine room relay block and junction block assembly.

*1	No. 1 Engine Room Relay Block and Junction Block Assembly
*2	INV W/P Relay Holder

Connect terminals 3 and 5 of the INV W/P relay holder.
HINT:

Make a short circuit between terminals 3 and 5 to supply +B voltage to the inverter water pump.

Measure the voltage according to the value(s) in the table below.

Component with harness connected
(Hybrid Vehicle Control ECU Assembly)

Front view of wire harness connector
(to Hybrid Vehicle Control ECU Assembly)

Standard Voltage

Tester Connection	Condition	Specified Condition
A29-34 (IWP) - A30-3 (E1)	INV W/P relay holder terminals 3 and 5 connected Ignition switch off	11 to 14 V

NOTE:

Make sure to check for and clear DTCs after performing this inspection.

Install the INV W/P relay.

Reconnect the A29 hybrid vehicle control ECU assembly connector.

Result

Proceed to
OK
NG

Result:

See step 15

Result:

See step 14

CHECK HYBRID VEHICLE CONTROL ECU ASSEMBLY (CHECK WAVEFORM)

Connect an oscilloscope between the hybrid vehicle control ECU assembly terminals specified in the table below.
Turn the ignition switch to ON.

Check the waveform while turning the ignition switch to ON.

Component with harness connected
(Hybrid Vehicle Control ECU Assembly)

Item	Content
Terminal	A29-34 (IWP) - A30-3 (E1)
Equipment Setting	5 V/DIV., 50 ms./DIV.
Condition	Ignition switch ON

Waveform duty ratio is between 3% and 9%.

Turn the ignition switch off.

Result

Proceed to
OK
NG

Result:

REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY

Result:

See step 15

REPLACE INVERTER WATER PUMP ASSEMBLY
Refer to REMOVAL [11/2018 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 16

ADD HV COOLANT AND PERFORM AIR BLEEDING

After replacing the inverter water pump assembly, add HV coolant and perform air bleeding.

Refer to REPLACEMENT [11/2018 - 12/2021] , or refer to REPLACEMENT [12/2021 - ]

Result

Proceed to
NEXT

Result:

END