HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): P314A31; Motor Electronics Coolant Pump "A" No Signal; 2023 - 2025 MY Corolla HV [09/2022

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM1000000026PUG
Model Year Start: 2023	Model: Corolla HV	Prod Date Range: [09/2022 - ]
Title: HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): P314A31; Motor Electronics Coolant Pump "A" No Signal; 2023 - 2025 MY Corolla HV [09/2022 - ]

DTC

P314A31

Motor Electronics Coolant Pump "A" No Signal

DESCRIPTION

Refer to the description for DTC P0C7396.

Click here

The inverter water pump assembly sends the inverter water pump speed (measured value) signal to the hybrid vehicle control ECU.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

Note

P314A31

Motor Electronics Coolant Pump "A" No Signal

The inverter water pump speed signal is not sent to the hybrid vehicle control ECU when the ignition switch is turned to ON (READY).*

(1 trip detection logic)

Wire harness or connector
Hybrid vehicle control ECU
Inverter water pump assembly
INV W/PMP fuse
INV W/PMP NO. 2 fuse
INV W/PMP relay

Comes on

Master Warning:

Comes on

SAE Code:

P314A

*: Any of the following conditions is met.

A malfunction (open, short to +B or short to ground) in the speed signal line from the inverter water pump assembly to the hybrid vehicle control ECU is detected.
A malfunction in the +B line is detected.
A malfunction in the inverter water pump assembly power source circuit is detected.
A malfunction in hybrid vehicle control ECU power source circuit is detected.

MONITOR DESCRIPTION

The hybrid vehicle control ECU monitors the speed of the inverter water pump assembly. If the inverter water pump speed signal is not sent to the hybrid vehicle control ECU, the hybrid vehicle control ECU will illuminate the MIL and store a DTC.

MONITOR STRATEGY

Related DTCs	P314A (INF P314A31): Inverter water pump malfunction
Required sensors/components	Inverter Water Pump Assembly
Frequency of operation	Continuous
Duration	TMC's intellectual property
MIL operation	Immediately
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not stored	TMC's intellectual property
Other conditions belong to TMC's intellectual property	-

TYPICAL MALFUNCTION THRESHOLDS

TMC's intellectual property

COMPONENT OPERATING RANGE

Hybrid vehicle control ECU

DTC P314A (INF P314A31) is not detected

CONFIRMATION DRIVING PATTERN

HINT:

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
Click here
When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
Click here

Connect the GTS to the DLC3.
Turn the ignition switch to ON and turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the ignition switch off and wait for 2 minutes or more.
Turn the ignition switch to ON and turn the GTS on.
Turn the ignition switch to ON (READY) and wait for 2 minutes or more. [*1]
HINT:

[*1]: Normal judgment procedure.

The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.
Check the DTC judgment result.
HINT:
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE, perform the normal judgment procedure again.

WIRING DIAGRAM

Refer to the wiring diagram for Cooling System.

Click here

PROCEDURE

CLEAR DTC

(a) Read and record the DTCs and Freeze Frame Data.

Powertrain > Hybrid Control > Trouble Codes

(b) Clear the DTCs and Freeze Frame Data.

Powertrain > Hybrid Control > Clear DTCs

2.	PERFORM ACTIVE TEST USING GTS (ACTIVATE THE INVERTER WATER PUMP)

NOTICE:

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 11 V or more.

HINT:

When the auxiliary battery voltage is low, the inverter water pump assembly may not operate.
When the inverter water pump assembly signal line (SWP - IWP) is open or its connection is faulty, the inverter water pump assembly is operated forcibly.

(a) Perform the "Activate the Inverter Water Pump" Active Test.

Powertrain > Hybrid Control > Active Test

Tester Display
Activate the Inverter Water Pump

(b) Touch the inverter water pump assembly and check that it is operating (vibrating).

OK:

The inverter water pump is operating (vibrating).

HINT:

Perform the Active Test with the inverter coolant temperature between -15 and 65°C (5 to 149°F).

GO TO STEP 9

3.	CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)

Click here

CONNECT SECURELY

4.	CHECK CONNECTOR CONNECTION CONDITION (INVERTER WATER PUMP ASSEMBLY CONNECTOR)

Click here

CONNECT SECURELY

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

(a) Disconnect the hybrid vehicle control ECU connector.

(b) Disconnect the inverter water pump assembly connector.

Standard Resistance (Check for Open):

Tester Connection	Condition	Specified Condition
A161-33 (NIWP) - A6-2 (NWP)	Ignition switch off	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
A161-33 (NIWP) or A6-2 (NWP) - Body ground and other terminals	Ignition switch off	10 kΩ or higher

HINT:

Check the condition (looseness, deterioration, etc.) of the wire to body ground for the inverter water pump assembly.

(d) Reconnect the inverter water pump assembly connector.

(e) Reconnect the hybrid vehicle control ECU connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK HYBRID VEHICLE CONTROL ECU

(a) Disconnect the inverter water pump assembly connector.

(b) Turn the ignition switch to ON.

Component with harness connected

(Hybrid Vehicle Control ECU)

Standard Voltage:

Tester Connection	Condition	Specified Condition
A161-33 (NIWP) - I3-1 (E1)	Ignition switch ON	11 to 14 V

(d) Turn the ignition switch off.

(e) Reconnect the inverter water pump assembly connector.

REPLACE HYBRID VEHICLE CONTROL ECU

CLEAR DTC

Click here

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

NOTICE:

Be sure to perform the inspection with the auxiliary battery voltage at 11 V or more.

HINT:

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

(a) Perform the "Activate the Inverter Water Pump" Active Test.

Powertrain > Hybrid Control > Active Test

Tester Display
Activate the Inverter Water Pump

(b) Connect an oscilloscope between the hybrid vehicle control ECU terminals specified in the table below, and measure the waveform.

Component with harness connected

(Hybrid Vehicle Control ECU)

Item	Content
Terminal	A161-33 (NIWP) - I3-1 (E1)
Equipment Setting	5 V/DIV., 5 ms./DIV.
Condition	Ignition switch ON, during Active Test

OK:

The period of the wavelength is 13 msec or less.

REPLACE HYBRID VEHICLE CONTROL ECU

GO TO STEP 15

9.	CHECK CONNECTOR CONNECTION CONDITION (INVERTER WATER PUMP ASSEMBLY CONNECTOR)

Click here

CONNECT SECURELY (INVERTER WATER PUMP ASSEMBLY CONNECTOR)

10.	CHECK INSTALLATION CONDITION (INV W/PMP RELAY)

(a) Check installation condition of the INV W/PMP relay.

OK:

INV W/PMP relay is installed correctly.

GO TO STEP 17

11.	CHECK HARNESS AND CONNECTOR (IGCT-MAIN NO. 2 RELAY - INV W/PMP RELAY)

(a) Remove the IGCT-MAIN NO. 2 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Remove the INV W/PMP relay from the No. 1 engine room relay block and No. 1 junction block assembly.

Standard Resistance:

Tester Connection	Condition	Specified Condition
5 (IGCT-MAIN NO. 2 relay holder) - 1 (INV W/PMP relay holder)	Ignition switch off	Below 1 Ω

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.

HINT:

Connectors
Slightly shake the connector vertically and horizontally.
Wire Harness
Slightly shake the wire harness vertically and horizontally.

The connector joint and fulcrum of the vibration are the major areas that should be checked thoroughly.
No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
Apply slight vibration with a finger to the No. 1 engine room relay block and No. 1 junction block assembly and check whether a malfunction occurs.
INV W/PMP fuse
Apply slight vibration with a finger to the INV W/PMP fuse and check whether a malfunction occurs.

*a	Example
*b	Shake Slightly
*c	Vibrate Slightly

(d) Install the IGCT-MAIN NO. 2 relay and INV W/PMP relay.

GO TO STEP 18

12.	INSPECT RELAY (INV W/PMP)

(a) Remove the INV W/PMP relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher
3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

*1	INV W/PMP Relay

GO TO STEP 20

13.	CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY - BODY GROUND)

*a	Example
*b	Shake Slightly
*c	Vibrate Slightly

(a) Disconnect the inverter water pump assembly connector.

(b) Turn the ignition switch to ON.

Standard Voltage:

Tester Connection	Condition	Specified Condition
A6-4 (+BWP) - Body ground	Ignition switch ON	11 to 14 V

NOTICE:

If the ignition switch is turned to ON with the connectors disconnected, other DTCs will be stored. Be sure to clear the DTCs after the inspection.
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.

HINT:

Connectors
Slightly shake the connector vertically and horizontally.
Wire Harness
Slightly shake the wire harness vertically and horizontally.

The connector joint and fulcrum of the vibration are the major areas that should be checked thoroughly.
No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
Apply slight vibration with a finger to the No. 1 engine room relay block and No. 1 junction block assembly and check whether a malfunction occurs.
INV W/PMP NO. 2 fuse
Apply slight vibration with a finger to the INV W/PMP NO. 2 fuse and check whether a malfunction occurs.
INV W/PMP Relay
Apply slight vibration with a finger to the INV W/PMP relay and check whether a malfunction occurs.

(d) Turn the ignition switch off.

(e) Reconnect the inverter water pump assembly connector.

GO TO STEP 21

14.	CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY - BODY GROUND)

(a) Disconnect the inverter water pump assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A6-1 (GND) - Body ground	Ignition switch off	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

15.	REPLACE INVERTER WATER PUMP ASSEMBLY

Click here

16.	ADD HV COOLANT AND PERFORM AIR BLEEDING

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

Click here

END

17.	INSPECT RELAY (INV W/PMP)

(a) Remove the INV W/PMP relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher
3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

*1	INV W/PMP Relay

CONNECT SECURELY (INV W/PMP RELAY)

REPLACE RELAY (INV W/PMP)

18.	CHECK INSTALLATION CONDITION (INV W/PMP FUSE)

(a) Check installation condition of the INV W/PMP fuse.

OK:

INV W/PMP fuse is installed correctly.

GO TO STEP 25

19.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
INV W/PMP fuse	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP FUSE HOLDER TERMINAL)

GO TO STEP 26

20.	CHECK RELAY HOLDER TERMINAL (INV W/PMP RELAY)

(a) Check the terminals of the INV W/PMP relay holder.

OK:

The terminals of the INV W/PMP relay holder are not bent, loose or corroded.

REPLACE RELAY (INV W/PMP)

GO TO STEP 27

21.	CHECK INSTALLATION CONDITION (INV W/PMP NO. 2 FUSE)

(a) Check installation condition of the INV W/PMP NO. 2 fuse.

OK:

INV W/PMP NO. 2 fuse is installed correctly.

CONNECT SECURELY (INV W/PMP NO. 2 FUSE)

22.	INSPECT RELAY (INV W/PMP)

(a) Remove the INV W/PMP relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher
3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

*1	INV W/PMP Relay

GO TO STEP 32

23.	CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY CIRCUIT)

(a) Remove the INV W/PMP NO. 2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Remove the INV W/PMP relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A6-4 (+BWP) - 3 (INV W/PMP relay holder)	Ignition switch off	Below 1 Ω
2 (INV W/PMP NO. 2 fuse holder) - 5 (INV W/PMP relay holder)	Ignition switch off	Below 1 Ω
2 (INV W/PMP NO. 2 fuse holder) or A6-4 (+BWP) - Body ground and other terminals	Ignition switch off	10 kΩ or higher

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.

(e) Reconnect the inverter water pump assembly connector.

(f) Install the INV W/PMP relay and INV W/PMP NO. 2 fuse.

REPAIR OR REPLACE HARNESS OR CONNECTOR

24.	CHECK FUSE (INV W/PMP NO. 2)

(a) Remove the INV W/PMP NO. 2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
INV W/PMP NO. 2 fuse	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP NO. 2 FUSE HOLDER TERMINAL OR INV W/PMP RELAY HOLDER TERMINAL)

GO TO STEP 28

25.	INSPECT RELAY (INV W/PMP)

(a) Remove the INV W/PMP relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 - 5	Auxiliary battery voltage not applied between terminals 1 and 2	10 kΩ or higher
3 - 5	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

*1	INV W/PMP Relay

CONNECT SECURELY (INV W/PMP FUSE)

GO TO STEP 30

26.	CHECK FUSE HOLDER TERMINAL (INV W/PMP FUSE)

(a) Check the terminals of the INV W/PMP fuse holder.

OK:

The terminals of the INV W/PMP fuse holder are not bent, loose or corroded.

REPLACE FUSE (INV W/PMP)

GO TO STEP 31

27.	REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP RELAY HOLDER TERMINAL)

(a) Repair or replace the terminals of the INV W/PMP relay holder.

REPLACE RELAY (INV W/PMP)

28.	REPLACE INVERTER WATER PUMP ASSEMBLY

Click here

29.	ADD HV COOLANT AND PERFORM AIR BLEEDING

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

Click here

REPLACE FUSE (INV W/PMP NO. 2)

30.	REPLACE RELAY (INV W/PMP)

CONNECT SECURELY (INV W/PMP FUSE)

31.	REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP FUSE HOLDER TERMINAL)

(a) Repair or replace the terminals of the INV W/PMP fuse holder.

REPLACE FUSE (INV W/PMP)

32.	CHECK RELAY HOLDER TERMINAL (INV W/PMP RELAY)

(a) Check the terminals of the INV W/PMP relay holder.

OK:

The terminals of the INV W/PMP relay holder are not bent, loose or corroded.

GO TO STEP 34

33.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
INV W/PMP fuse	Always	Below 1 Ω

REPLACE RELAY (INV W/PMP)

GO TO STEP 36

34.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
INV W/PMP fuse	Always	Below 1 Ω

GO TO STEP 37

35.	REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP RELAY HOLDER TERMINAL)

(a) Repair or replace the terminals of the INV W/PMP relay holder.

REPLACE RELAY (INV W/PMP)

36.	REPLACE RELAY (INV W/PMP)

REPLACE FUSE (INV W/PMP)

37.	REPAIR OR REPLACE HARNESS OR CONNECTOR (INV W/PMP RELAY HOLDER TERMINAL)

(a) Repair or replace the terminals of the INV W/PMP relay holder.

38.	REPLACE RELAY (INV W/PMP)

REPLACE FUSE (INV W/PMP)