Lexus ES: Motor Electronics Coolant Pump "A" No Signal (P314A31)

Lexus ES (XZ10) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Control System (for Lithium-ion Battery) / Motor Electronics Coolant Pump "A" No Signal (P314A31)

DESCRIPTION

Refer to the description for DTC P0C7396.

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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
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 power switch is turned on (READY).* (1 trip detection logic)	Wire harness or connector Hybrid vehicle control ECU Inverter water pump assembly INV W/PMP fuse IGCT relay IGCT fuse	Comes on	Master Warning Light: Comes on

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Warning Indicate

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 power switch is turned on (READY).*

(1 trip detection logic)

Wire harness or connector
Hybrid vehicle control ECU
Inverter water pump assembly
INV W/PMP fuse
IGCT relay
IGCT fuse

Comes on

Master Warning Light:

Comes on

*: Either 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.

Related Data List

DTC No.	Data List
P314A31	Inverter Water Pump Revolution Inverter Water Pump Duty Ratio Ready Signal

Related Active Test

DTC No.	Active Test
P314A31	Activate the Inverter Water Pump

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 Techstream to the DLC3.
Turn the power switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for 2 minutes or more.
Turn the power switch on (IG) and turn the Techstream on.
Turn the power switch 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 or N/A, perform the normal judgment procedure again.

WIRING DIAGRAM

Refer to the wiring diagram for DTC P0C7396.

Click here

PROCEDURE

CLEAR DTC

Click here

2.	PERFORM ACTIVE TEST USING TECHSTREAM (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 12 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) Connect the Techstream to the DLC3.

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

Powertrain > Hybrid Control > Active Test

Tester Display
Activate the Inverter Water Pump

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

(e) 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).

(f) Turn the power switch off.

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 A32 hybrid vehicle control ECU connector.

(b) Disconnect the Z1 inverter water pump assembly connector.

Standard Resistance (Check for Open):

Tester Connection	Condition	Specified Condition
A32-14 (NIWP) - Z1-2 (NWP)	Power switch off	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
A32-14 (NIWP) or Z1-2 (NWP) -Body ground and other terminals	Power 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.

Rear view of wire harness connector

(to Hybrid Vehicle Control ECU)

Front view of wire harness connector

(to Inverter Water Pump Assembly)

(d) Reconnect the Z1 inverter water pump assembly connector.

(e) Reconnect the A32 hybrid vehicle control ECU connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK HYBRID VEHICLE CONTROL ECU

(a) Disconnect the Z1 inverter water pump assembly connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A32-14 (NIWP) - G59-6 (E1)	Power switch on (IG)	11 to 14 V

*a	Component with harness connected (Hybrid Vehicle Control ECU)

(d) Turn the power switch off.

(e) Reconnect the Z1 inverter water pump assembly connector.

REPLACE HYBRID VEHICLE CONTROL ECU

CLEAR DTC

Click here

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

NOTICE:

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.

(a) Connect the Techstream to the DLC3.

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

Powertrain > Hybrid Control > Active Test

Tester Display
Activate the Inverter Water Pump

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

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

Item	Content
Terminal	A32-14 (NIWP) - G59-6 (E1)
Equipment Setting	5 V/DIV., 5 ms./DIV.
Condition	Power switch on (IG), during Active Test

OK:

The period of the wavelength is 13 msec or less.

*a	Component with harness connected (Hybrid Vehicle Control ECU)

(f) Turn the power switch off.

REPLACE HYBRID VEHICLE CONTROL ECU

GO TO STEP 12

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

Click here

GO TO STEP 14

10.	CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP ASSEMBLY - IGCT RELAY)

(a) Remove the IGCT relay from the No. 3 relay block.

(b) Disconnect the Z1 inverter water pump assembly connector.

No. 3 Relay Block

IGCT Relay Holder

Front view of wire harness connector

(to Inverter Water Pump Assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
Z1-4 (+BWP) - 5 (IGCT relay holder)	Power 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. 3 Relay Block
Apply slight vibration with a finger to the No. 3 relay block 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.
IGCT relay
Apply slight vibration with a finger to the IGCT relay and check whether a malfunction occurs.

*a	Example
*b	Shake Slightly
*c	Vibrate Slightly

(d) Reconnect the Z1 inverter water pump assembly connector.

(e) Install the IGCT relay.

GO TO STEP 15

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

(a) Disconnect the Z1 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
Z1-1 (GND) - Body ground	Power switch off	Below 1 Ω

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.	REPLACE INVERTER WATER PUMP ASSEMBLY

Click here

13.	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

14.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse from the No. 4 relay block.

*1	No. 4 Relay Block
*2	INV W/PMP Fuse

(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

CONNECT SECURELY (INVERTER WATER PUMP ASSEMBLY CONNECTOR)

GO TO STEP 18

15.	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 19

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

(a) Remove the INV W/PMP fuse from No. 4 relay block.

(b) Remove the IGCT relay from the No. 3 relay block.

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

No. 3 Relay Block

IGCT Relay Holder

No. 4 Relay Block

INV W/PMP Fuse Holder

Front view of wire harness connector

(to Inverter Water Pump Assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
2 (INV W/PMP fuse holder) - Z1-4 (+BWP)	Power switch off	Below 1 Ω
1 (INV W/PMP fuse holder) - 5 (IGCT relay holder)	Power switch off	Below 1 Ω
2 (INV W/PMP fuse holder) or Z1-4 (+BWP) - Body ground and other terminals	Power 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 Z1 inverter water pump assembly connector.

(f) Install the IGCT relay.

(g) Install the INV W/PMP fuse.

GO TO STEP 21

17.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse from the No. 4 relay block.

*1	No. 4 Relay Block
*2	INV W/PMP Fuse

(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 22

18.	CONNECT SECURELY

(a) Connect the inverter water pump assembly connector securely.

REPLACE FUSE (INV W/PMP)

19.	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.

GO TO STEP 26

20.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse from the No. 4 relay block.

*1	No. 4 Relay Block
*2	INV W/PMP Fuse

(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

CONNECT SECURELY (INV W/PMP FUSE)

REPLACE FUSE (INV W/PMP)

21.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse from the No. 4 relay block.

*1	No. 4 Relay Block
*2	INV W/PMP Fuse

(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

GO TO STEP 27

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

(a) Disconnect the Z1 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
Z1-1 (GND) - Body ground	Power switch off	Below 1 Ω

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

GO TO STEP 27

23.	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.

GO TO STEP 28

24.	REPLACE INVERTER WATER PUMP ASSEMBLY

Click here

25.	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)

26.	CHECK FUSE (INV W/PMP)

(a) Remove the INV W/PMP fuse from the No. 4 relay block.

*1	No. 4 relay block
*2	INV W/PMP Fuse

(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 28

27.	REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE FUSE (INV W/PMP)

28.	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)

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