DTC P314A-31: Motor Electronics Coolant Pump "A" No Signal [12/2019 - 11/2023]: Procedure

1. Read and record the DTCs and Freeze Frame Data.

   Powertrain > Hybrid Control > Trouble Codes 

2. Clear the DTCs and Freeze Frame Data.

   Powertrain > Hybrid Control > Clear DTCs 

3. Turn the ignition switch off and wait for 2 minutes or more.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

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.

1. Perform the "Activate the Inverter Water Pump" Active Test.

   Powertrain > Hybrid Control > Active Test 

   Tester Display
   Activate the Inverter Water Pump

2. 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).

3. Turn the ignition switch off.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  3

Refer to PROCEDURE - Step 1

Result

Result: 

NG 

CONNECT SECURELY 

Result: 

OK 

See step  4

Refer to PROCEDURE - Step 10 [12/2019 - 10/2021] , or refer to PROCEDURE - Step 10 [10/2021 - 11/2023]

Result

Result: 

NG 

CONNECT SECURELY 

Result: 

OK 

See step  5

1. Disconnect the A31 hybrid vehicle control ECU connector.
2. Disconnect the A56 inverter water pump assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   A31-33 (NIWP) - A56-2 (NWP)	Ignition switch off	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   A31-33 (NIWP) or A56-2 (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.

4. Reconnect the A56 inverter water pump assembly connector.
5. Reconnect the A31 hybrid vehicle control ECU connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Disconnect the A56 inverter water pump assembly connector.
2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component with harness connected (Hybrid Vehicle Control ECU)

   -

   -

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A31-33 (NIWP) - H67-3 (E1)	Ignition switch ON	11 to 14 V

4. Turn the ignition switch off.
5. Reconnect the A56 inverter water pump assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE HYBRID VEHICLE CONTROL ECU 

Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

Result: 

OK 

See step  7

Refer to PROCEDURE - Step 3

Result

Result: 

NEXT 

See step  8

HINT: 

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

1. Perform the "Activate the Inverter Water Pump" Active Test.

   Powertrain > Hybrid Control > Active Test 

   Tester Display
   Activate the Inverter Water Pump

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component with harness connected (Hybrid Vehicle Control ECU)

   -

   -

   Item	Content
   Terminal	A31-33 (NIWP) - H67-3 (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.

3. Turn the ignition switch off.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE HYBRID VEHICLE CONTROL ECU 

Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

Result: 

NG 

See step  15

Refer to PROCEDURE - Step 10 [12/2019 - 10/2021] , or refer to PROCEDURE - Step 10 [10/2021 - 11/2023]

Result

Result: 

NG 

CONNECT SECURELY (INVERTER WATER PUMP ASSEMBLY CONNECTOR) 

Result: 

OK 

See step  10

1. Check installation condition of the INV W/PMP relay.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   OK

   INV W/PMP relay is installed correctly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  17

Result: 

OK 

See step  11

1. Remove the IGCT relay from the No. 5 floor relay block and No. 5 floor junction block assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 5 Floor Relay Block and No. 5 Floor Junction Block Assembly
   *2	IGCT Relay Holder

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   5 (IGCT relay holder) - 1 (INV W/PMP relay holder)	Ignition switch off	Below 1 Ω

   NOTE:

   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. 5 Floor Relay Block and No. 5 Floor Junction Block Assembly

     Apply slight vibration with a finger to the No. 5 floor relay block and No. 5 floor junction block assembly and check whether a malfunction occurs.

   • 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.

   • IGCT NO. 2 fuse

     Apply slight vibration with a finger to the IGCT NO. 2 fuse and check whether a malfunction occurs.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Example
   *b	Shake Slightly
   *c	Vibrate Slightly

4. Install the IGCT relay and INV W/PMP relay.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  18

Result: 

OK 

See step  12

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

2. 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
   	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	INV W/PMP Relay

3. Install the INV W/PMP relay.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  20

Result: 

OK 

See step  13

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the A56 inverter water pump assembly connector.
2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A56-4 (+BWP) - Body ground	Ignition switch ON	11 to 14 V

   NOTE:

   • 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 fuse

     Apply slight vibration with a finger to the INV W/PMP 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.

4. Turn the ignition switch off.
5. Reconnect the A56 inverter water pump assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  21

Result: 

OK 

See step  14

1. Disconnect the A56 inverter water pump assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Inverter Water Pump Assembly)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A56-1 (GND) - Body ground	Ignition switch off	Below 1 Ω

3. Reconnect the A56 inverter water pump assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  15

Refer to REMOVAL [12/2019 - ]

Result

Result: 

NEXT 

See step  16

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

   Refer to REPLACEMENT [12/2019 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

END 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

2. 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
   	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	INV W/PMP Relay

3. Install the INV W/PMP relay.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

CONNECT SECURELY (INV W/PMP RELAY) 

Result: 

NG 

REPLACE RELAY (INV W/PMP) 

1. Check installation condition of the IGCT NO. 2 fuse.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 5 Floor Relay Block and No. 5 Floor Junction Block Assembly
   *2	IGCT NO. 2 Fuse

   OK

   IGCT NO. 2 fuse is installed correctly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  25

Result: 

OK 

See step  19

1. Remove the IGCT NO. 2 fuse from the No. 5 floor relay block and No. 5 floor junction block assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 5 Floor Relay Block and No. 5 Floor Junction Block Assembly
   *2	IGCT NO. 2 Fuse

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   IGCT NO. 2 fuse	Always	Below 1 Ω

3. Install the IGCT NO. 2 fuse.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPAIR OR REPLACE HARNESS OR CONNECTOR (IGCT NO. 2 FUSE HOLDER TERMINAL) 

Result: 

NG 

See step  26

1. 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.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE RELAY (INV W/PMP) 

Result: 

NG 

See step  27

1. Check installation condition of the INV W/PMP fuse.

   OK

   INV W/PMP fuse is installed correctly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CONNECT SECURELY (INV W/PMP FUSE) 

Result: 

OK 

See step  22

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

2. 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
   	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	INV W/PMP Relay

3. Install the INV W/PMP relay.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  32

Result: 

OK 

See step  23

1. Remove the INV W/PMP relay and INV W/PMP fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
2. Disconnect the A56 inverter water pump assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly	*2	INV W/PMP Relay Holder
   *3	INV W/PMP Fuse	-	-
   *a	Front view of wire harness connector (to Inverter Water Pump Assembly)	-	-

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A56-4 (+BWP) - 3 (INV W/PMP relay holder)	Ignition switch off	Below 1 Ω
   2 (INV W/PMP fuse holder) or A56-4 (+BWP) - Body ground and other terminals	Ignition switch off	10 kΩ or higher

   NOTE:

   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.

4. Reconnect the A56 inverter water pump assembly connector.
5. Install the INV W/PMP relay and INV W/PMP fuse.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  24

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

2. 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

3. Install the INV W/PMP fuse.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

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

Result: 

NG 

See step  28

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

2. 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
   	Auxiliary battery voltage applied between terminals 1 and 2	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	INV W/PMP Relay

3. Install the INV W/PMP relay.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

CONNECT SECURELY (IGCT NO. 2 FUSE) 

Result: 

NG 

See step  30

1. Check the terminals of the IGCT NO. 2 fuse holder.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 5 Floor Relay Block and No. 5 Floor Junction Block Assembly
   *2	IGCT NO. 2 Fuse

   OK

   The terminals of the IGCT NO. 2 fuse holder are not bent, loose or corroded.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE FUSE (IGCT NO. 2) 

Result: 

NG 

See step  31

1. Repair or replace the terminals of the INV W/PMP relay holder.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

REPLACE RELAY (INV W/PMP) 

Refer to REMOVAL [12/2019 - ]

Result

Result: 

NEXT 

See step  29

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

   Refer to REPLACEMENT [12/2019 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

REPLACE FUSE (INV W/PMP) 

Result

Result: 

NEXT 

CONNECT SECURELY (IGCT NO. 2 FUSE) 

1. Repair or replace the terminals of the IGCT NO. 2 fuse holder.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

REPLACE FUSE (IGCT NO. 2) 

1. 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.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  34

Result: 

OK 

See step  33

1. Remove the IGCT NO. 2 fuse from the No. 5 floor relay block and No. 5 floor junction block assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 5 Floor Relay Block and No. 5 Floor Junction Block Assembly
   *2	IGCT NO. 2 Fuse

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   IGCT NO. 2 fuse	Always	Below 1 Ω

3. Install the IGCT NO. 2 fuse.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE RELAY (INV W/PMP) 

Result: 

NG 

See step  36

1. Remove the IGCT NO. 2 fuse from the No. 5 floor relay block and No. 5 floor junction block assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *1	No. 5 Floor Relay Block and No. 5 Floor Junction Block Assembly
   *2	IGCT NO. 2 Fuse

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   IGCT NO. 2 fuse	Always	Below 1 Ω

3. Install the IGCT NO. 2 fuse.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  37

Result: 

OK 

See step  35

1. Repair or replace the terminals of the INV W/PMP relay holder.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

REPLACE RELAY (INV W/PMP) 

Result

Result: 

NEXT 

REPLACE FUSE (IGCT NO. 2) 

1. Repair or replace the terminals of the INV W/PMP relay holder.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  38

Result

Result: 

NEXT 

REPLACE FUSE (IGCT NO. 2)