P0A01

HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM: P0A01-725,P0A01-726: Motor Electronics Coolant Temperature Sensor Circuit Range / Performance
P0A01-726 - Motor Electronics Coolant Temperature Sensor Circuit Range / Performance

DESCRIPTION

The hybrid vehicle control ECU detects HV coolant temperature using the coolant temperature sensor built into the inverter with converter assembly. The hybrid vehicle control ECU uses signals from the coolant temperature sensor to check the effectiveness of the inverter cooling system. If necessary, the hybrid vehicle control ECU will limit inverter output to help prevent inverter overheating. The hybrid vehicle control ECU also detects malfunctions in the sensor based on the HV coolant temperature sensor values. The inverter with converter assembly detects malfunctions in the HV coolant temperature sensor and its wiring.

WIRING DIAGRAM

INSPECTION PROCEDURE

CAUTION:
- Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
- After disconnecting the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.
HINT
Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

PROCEDURE

1. CHECK DTC OUTPUT (HV)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

(d) Check if DTCs are output.

Result:

HINT
P0A01-725 or P0A01-726 may be set due to a malfunction which also causes the DTC in the preceding table to be set. In this case, first troubleshoot the output DTC in the preceding table. Then, perform a test to attempt to reproduce the problems, and check that no DTCs are output.

B -- GO TO DTC CHART Hybrid Control System
A -- Continue to next step.

2. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR) P0343

NG -- CONNECT SECURELY
OK -- Continue to next step.

3. CHECK QUANTITY OF HV COOLANT

(a) Check the coolant level in the inverter reserve tank assembly.

(b) Check for coolant leaks.

Result:

HINT
After repairing the coolant leaks and adding coolant, perform the "Activate the Water Pump" Active Test (HV Active Test item) and the "Control the Electric Cooling Fan" Active Test (Engine Active Test item) and make sure that there are no malfunctions.

C -- INSPECT COOLANT LEAK AND ADD COOLANT

B -- ADD COOLANT
A -- Continue to next step.

4. CHECK COOLANT HOSE

(a) Check if the hoses of the cooling system are kinked or clogged.

OK:

The hoses are not kinked or clogged.

NG -- CORRECT THE PROBLEM
OK -- Continue to next step.

5. PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE WATER PUMP)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Enter the following menus: Powertrain / Hybrid Control / Active Test / Activate the Water Pump.

(d) Perform the "Activate the Water Pump" active test.

(e) During the "Activate the Water Pump" active test, open the inverter reserve tank cap and check that there are ripples in the coolant. Continue the active test for at least 1 minute.

OK:

There are ripples in the coolant in the inverter reserve tank assembly for 1 minute.

NOTICE:
To prevent the coolant from spilling, be sure to close the inverter reserve tank cap before turning the power switch off or before ending the Active Test.

(f) Turn the power switch off.

NG -- PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE WATER PUMP)
OK -- Continue to next step.

6. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE ELECTRIC COOLING FAN)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Electric Cooling Fan.

(d) Perform the "Control the Electric Cooling Fan" Active Test.

OK:

The cooling fan rotates.

(e) Turn the power switch off.

NG -- CHECK COOLING FAN SYSTEM Cooling Fan Circuit
OK -- Continue to next step.

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

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Read the freeze frame data Ambient Temperature using the Techstream.

(d) Check if the freeze frame data Ambient Temperature is below freezing.

Result:

HINT
- HV coolant (SLLC) with a 30% concentration freezes at 5°F (-15 °C) and HV coolant (SLLC) with a 50% concentration freezes at -31°F (-35°C).
- If the HV coolant freezes in the HV radiator or HV 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 set.
- A DTC is set when the water pump impeller cannot rotate due to freezing of the HV coolant.
- If a DTC is set due to freezing of HV coolant, the problem cannot be reproduced. Judge whether freezing of HV coolant occurred according to the freeze point of the HV coolant, HV coolant change history and ambient temperature when the DTC was set.
(e) Turn the power switch off.

B -- REPLACE HV COOLANT

A -- REPLACE INVERTER WITH CONVERTER ASSEMBLY Components

8. PERFORM ACTIVE TEST USING TECHSTREAM (ACTIVATE THE WATER PUMP)

(a) Connect the Techstream to the DLC3.

(b) Compress the inlet hose for the water pump with motor assembly several times.

HINT
Keep compressing the water pump inlet hose until the coolant level in the inverter reserve tank assembly stops dropping.

(c) Turn the power switch on (IG).

(d) Enter the following menus: Powertrain / Hybrid Control / Active Test / Activate the Water Pump.

(e) Perform the "Activate the Water Pump" active test.

(f) During the "Activate the Water Pump" active test, open the inverter reserve tank cap and check that there are ripples in the coolant. Continue the active test for at least 1 minute.

OK:

There are ripples in the coolant in the inverter reserve tank assembly for 1 minute.

Result:

NOTICE:
To prevent the coolant from spilling, be sure to close the inverter reserve tank cap before turning the power switch off or before ending the Active Test.

(g) Turn the power switch off.

B -- ADD COOLANT
A -- Continue to next step.

9. CHECK FUSE (IGCT NO. 3)

(a) Remove the IGCT No. 3 fuse from the engine room junction block assembly.

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

Standard Resistance:

Text in Illustration

(c) Install the IGCT No. 3 fuse.

NG -- CHECK CONNECTOR CONNECTION CONDITION (WATER PUMP WITH MOTOR ASSEMBLY CONNECTOR)
OK -- Continue to next step.

10. CHECK CONNECTOR CONNECTION CONDITION (WATER PUMP WITH MOTOR ASSEMBLY CONNECTOR)

(a) Check the connection of the water pump with motor assembly connector.

OK:

The connector is connected securely and there are no contact problems.

NG -- CONNECT SECURELY
OK -- Continue to next step.

11. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) P0343

NG -- CONNECT SECURELY
OK -- Continue to next step.

12. CHECK HARNESS AND CONNECTOR (WATER PUMP WITH MOTOR ASSEMBLY CIRCUIT)

(a) Remove the IGCT No. 3 fuse from the engine room junction block assembly.

(b) Remove the IGCT relay from the engine room junction block assembly.

(c) Disconnect connector A58 from the hybrid vehicle control ECU.

(d) Disconnect connector A33 from the water pump with motor assembly.

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

Text in Illustration

Standard Resistance:

NOTICE:
Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.

(f) Install the IGCT No. 3 fuse.

(g) Install the IGCT relay.

(h) Connect the hybrid vehicle control ECU connector.

(i) Connect the water pump with motor assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

13. CHECK WATER PUMP WITH MOTOR ASSEMBLY

(a) Remove the IGCT No. 3 fuse from the engine room junction block assembly.

Text in Illustration

OK:

The connector is connected securely and there are no contact problems.

NG -- CONNECT SECURELY
OK -- Continue to next step.

15. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) P0343

NG -- CONNECT SECURELY
OK -- Continue to next step.

16. CHECK HARNESS AND CONNECTOR (WATER PUMP WITH MOTOR ASSEMBLY CIRCUIT)

(a) Remove the IGCT No. 3 fuse from the engine room junction block assembly.

(b) Disconnect connector A33 from the water pump with motor assembly.

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

Standard Resistance:

Text in Illustration

NOTICE:
Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.

(d) Install the IGCT No. 3 fuse.

(e) Connect the water pump with motor assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

17. CHECK WATER PUMP WITH MOTOR ASSEMBLY

(a) Remove the IGCT No. 3 fuse from the engine room junction block assembly.

Text in Illustration

(b) Apply 12 V to terminal 2 of the IGCT No. 3 fuse holder of the engine room junction block assembly.

(c) Check that the water pump operates.

OK:

The water pump operates.

NOTICE:
Do not apply excessive force when using the probes of the tester to perform the inspection. If excessive force is used, the terminals will be damaged.

(d) Install the IGCT No. 3 fuse.

NG -- REPLACE WATER PUMP WITH MOTOR ASSEMBLY
OK -- Continue to next step.

18. REPLACE HYBRID VEHICLE CONTROL ECU

(a) Replace the hybrid vehicle control ECU Components.

NEXT -- REPLACE FUSE (IGCT NO. 3)

19. REPLACE HV COOLANT

(a) Replace the HV coolant with coolant having an appropriate concentration (appropriate freeze point) for the vehicle usage conditions Service and Repair.

NEXT -- Continue to next step.

20. CHECK WATER PUMP WITH MOTOR ASSEMBLY

(a) Perform a road test and check that water pump related DTCs are not stored.

OK:

DTCs are not stored.

NG -- REPLACE WATER PUMP WITH MOTOR ASSEMBLY Components

OK -- COMPLETED

21. CONNECT SECURELY

(a) Connect the water pump with motor assembly connector securely.

NEXT -- REPLACE FUSE (IGCT NO. 3)

22. CONNECT SECURELY

(a) Connect the hybrid vehicle control ECU connectors securely.

NEXT -- REPLACE FUSE (IGCT NO. 3)

23. REPAIR OR REPLACE HARNESS OR CONNECTOR

(a) Repair or replace the wire harness or connector.

NEXT -- REPLACE FUSE (IGCT NO. 3)

24. REPLACE WATER PUMP WITH MOTOR ASSEMBLY

(a) Replace the water pump with motor assembly Components.

NEXT -- REPLACE FUSE (IGCT NO. 3)