RX400h · Service Manual HEATER & AIR CONDITIONING SYSTEM

Heater Water Pump Circuit

Circuit diagnosis

DESCRIPTION

The heater water pump assembly sends engine coolant to the heater core assembly while the engine is stopped to prevent heater effectiveness from becoming low. Directed by the air conditioning amplifier assembly, the hybrid vehicle control ECU operates the water pump relay and drives the heater water pump assembly.
System diagram of the power distributor (Click here).
System description of the power distributor (Click here).

WIRING DIAGRAM

E109246E04

INSPECTION PROCEDURE


1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and push the intelligent tester main switch on.

  1. Select the item below in the ACTIVE TEST and check that the relay operates.

    ACTIVE TEST / AIR CONDITIONER 
    Item
    		 Test Details/Display
    (Range)
    		 Diagnostic Note
    WATER PUMP
    		 Water pump / OFF, ON
    		 -

    OK:
    Heater water pump operates smoothly.



 NG
Go to step 2
OK

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and push the intelligent tester main switch on.

  1. Select the item below in the ACTIVE TEST and check that the water pump operates.

    ACTIVE TEST / HYBRID CONTROL SYSTEM 
    Item
    		 Test Details/Display
    (Range)
    		 Diagnostic Note
    WATER PUMP
    		 Activate the Water Pump / OFF, ON
    		 -

    OK:
    Heater water pump operates smoothly.



 NG
Go to step 3
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

3. INSPECT MODE MONITOR TERMINAL

  1. Remove the cover of the fusible link block assembly.

  1. Turn the ignition switch ON.

  1. Measure the voltage when the following conditions are established.

    1. Perform ACTIVE TEST by using the intelligent tester.

    2. Operates the heater water pump.

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

    Result:
    Result
    		 Proceed to
    Below 2 V
    		 A
    More than 4 V
    		 B



B
Go to step 7
A


4. CHECK HARNESS AND CONNECTOR (J/B NO.2 - BODY GROUND)

  1. E109287E02
    Disconnect the connector from J/B No.2 (2D).

  1. Turn the ignition switch ON.

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

    Voltage:
    Tester connection
    		 Condition
    		 Specified condition
    2D-2 - Body ground
    		 Blower switch: ON
    		 10 to 14 V
    2D-2 - Body ground
    		 Blower switch: OFF
    		 Below 1 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5. INSPECT HEATER WATER PUMP ASSEMBLY

  1. Remove the heater water pump assembly.

  1. E109284E03
    Disconnect the connector from the heater water pump assembly.

  1. Connect the positive (+) lead to terminal 2 of the heater water pump assembly connector and the negative (-) lead to terminal 1.

    OK:
    Heater water pump operates smoothly.

    NOTICE:
    Complete operation within 10 seconds if there is no water in the heater water pump assembly.



 NG
REPLACE HEATER WATER PUMP ASSEMBLY
OK


6. INSPECT J/B NO.2 (A/C W/P RELAY)

  1. Turn the ignition switch off.

  1. Remove the J/B No.2.

  1. E109292E02
    Disconnect the connectors from the J/B No.2.

  1. Connect the positive (+) lead from the battery to terminal 2D-2 (WPB) and the negative (-) lead to terminals 2H-13 (SGND) and 2F-1 (PGND).

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    2C-1 (WPL) - 2H-13 (SGND)
    		 Always
    		 Below 1 V

  1. Connect the positive (+) lead from battery to terminal 2D-2 (WPB) and the negative (-) lead to terminals 2H-13 (SGND), 2F-1 (PGND) and 2H-10 (WP).

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    2C-1 (WPL) - 2H-13 (SGND)
    		 Always
    		 10 to 14 V



NG
REPLACE J/B NO.2 (A/C W/P RELAY)
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATER WATER PUMP ASSEMBLY - J/B NO.2 OR BODY GROUND)

7. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND)

  1. E109299E04
    Disconnect the connector from the hybrid vehicle control ECU.

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    H31-4 (WP) - Body ground
    		 Ignition switch: ON
    		 10 to 14 V
    H31-4 (WP) - Body ground
    		 Ignition switch: OFF
    		 Below 1 V



NG
Go to step 11
OK


8. INSPECT HYBRID VEHICLE CONTROL ECU

  1. E108916E15
    Reconnect the connectors to the hybrid vehicle control ECU.

  1. Turn the ignition switch ON.

  1. Measure the voltage when these conditions are established.Test conditions:

    1. Perform ACTIVE TEST by the intelligent tester.

    2. Operates the heater water pump.

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    H31-4 (WP) - Body ground
    		 Not operate the heater water pump
    		 10 to 14 V
    H31-4 (WP) - Body ground
    		 Operate the heater water pump
    		 Below 1 V



NG
REPLACE HYBRID VEHICLE CONTROL ECU
OK


9. INSPECT HEATER WATER PUMP ASSEMBLY

  1. Remove the heater water pump assembly.

  1. E109284E03
    Disconnect the connector from the heater water pump assembly.

  1. Connect the positive (+) lead to terminal 2 of the heater water pump assembly connector and the negative (-) lead to terminal 1.

    OK:
    Heater water pump operates smoothly.

    NOTICE:
    Complete operation within 10 seconds if there is no water in the heater water pump assembly.



 NG
REPLACE HEATER WATER PUMP ASSEMBLY
OK


10. INSPECT J/B NO.2 (A/C W/P RELAY)

  1. Turn the ignition switch off.

  1. Remove the J/B No.2.

  1. E109292E02
    Disconnect the connectors from the J/B No.2.

  1. Connect the positive (+) lead from the battery to terminal 2D-2 (WPB) and the negative (-) lead to terminals 2H-13 (SGND) and 2F-1 (PGND).

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    2C-1 (WPL) - 2H-13 (SGND)
    		 Always
    		 Below 1 V

  1. Connect the positive (+) lead from battery to terminal 2D-2 (WPB) and the negative (-) lead to terminals 2H-13 (SGND), 2F-1 (PGND) and 2H-10 (WP).

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    2C-1 (WPL) - 2H-13 (SGND)
    		 Always
    		 10 to 14 V



NG
REPLACE J/B NO.2 (A/C W/P RELAY)
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATER WATER PUMP ASSEMBLY - J/B NO.2 OR BODY GROUND)

11. CHECK HARNESS AND CONNECTOR (J/B NO.2 - BODY GROUND)

  1. E109287E02
    Disconnect the connector from the J/B No.2 (2D).

  1. Turn the ignition switch ON.

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

    Voltage:
    Tester connection
    		 Condition
    		 Specified condition
    2D-2 - Body ground
    		 Blower switch: ON
    		 10 to 14 V
    2D-2 - Body ground
    		 Blower switch: OFF
    		 Below 1 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


12. INSPECT J/B NO.2 (A/C W/P RELAY)

  1. Turn the ignition switch off.

  1. Remove the J/B No.2.

  1. E109292E02
    Disconnect the connectors from the J/B No.2.

  1. Connect the positive (+) lead from the battery to terminal 2D-2 (WPB) and the negative (-) lead to terminals 2H-13 (SGND) and 2F-1 (PGND).

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    2C-1 (WPL) - 2H-13 (SGND)
    		 Always
    		 Below 1 V

  1. Connect the positive (+) lead from battery to terminal 2D-2 (WPB) and the negative (-) lead to terminals 2H-13 (SGND), 2F-1 (PGND) and 2H-10 (WP).

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    2C-1 (WPL) - 2H-13 (SGND)
    		 Always
    		 10 to 14 V



NG
REPLACE J/B NO.2 (A/C W/P RELAY)
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATER WATER PUMP ASSEMBLY - J/B NO.2 OR BODY GROUND)


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