Heater Water Pump Circuit

AIR CONDITIONING SYSTEM: Heater Water Pump Circuit

Heater Water Pump Circuit

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, hybrid vehicle control ECU operates the water pump relay and drives the heater water pump assembly.
System diagram of the power distributor Description and Operation.
System description of the power distributor Description and Operation.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST BY TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and push the Techstream main switch on.
(c) Select the item below in the ACTIVE TEST and check that the relay operates.

Air Conditioner

OK:
Heater water pump operates smoothly.
NG -- PERFORM ACTIVE TEST BY TECHSTREAM
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2. PERFORM ACTIVE TEST BY TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and push the Techstream main switch on.
(c) Select the item below in the ACTIVE TEST and check that the water pump operates.

Hybrid Control system

OK:
Heater water pump operates smoothly.
NG -- INSPECT MODE MONITOR TERMINAL
OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
3. INSPECT MODE MONITOR TERMINAL
(a) Remove the cover of the fusible link block assembly.
(b) Turn the ignition switch ON.
(c) Measure the voltage when the conditions are established.
(1) Perform the ACTIVE TEST by using the Techstream.
(2) Operates the heater water pump.
(d) Measure the voltage according to the value(s) in the table below.
Result:

B -- CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND)
A -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (J/B NO.2 - BODY GROUND)

(a) Disconnect the connector from J/B No.2 (2D).
(b) Turn the ignition switch ON.
(c) Measure the voltage according to the value(s) in the table below.
Voltage:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. INSPECT HEATER WATER PUMP ASSEMBLY
(a) Remove the heater water pump assembly.

(b) Disconnect the connector from the heater water pump assembly.
(c) 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.
NOTE: Complete operation within 10 seconds if there is no water in the heater water pump assembly.

NG -- REPLACE HEATER WATER PUMP ASSEMBLY
OK -- Continue to next step.
6. INSPECT J/B NO.2 (A/C W/P RELAY)
(a) Turn the ignition switch off.
(b) Remove the J/B No.2.

(c) Disconnect the connectors from the J/B No.2.
(d) Connect the positive (+) lead from the battery to terminal 2D-2 (WPB) and the negative (-) lead to terminal 2H-13 (SGND) and 2F-1 (PGND).
(e) Measure the voltage according to the value(s) in the table below.
Voltage:

(f) 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).
(g) Measure the voltage according to the value(s) in the table below.
Voltage:

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)
(a) Disconnect the connector from the hybrid vehicle control ECU.

(b) Measure the voltage according to the value(s) in the table below.
Voltage:

NG -- CHECK HARNESS AND CONNECTOR (J/B NO.2 - BODY GROUND)
OK -- Continue to next step.
8. INSPECT HYBRID VEHICLE CONTROL ECU

(a) Reconnect the connectors to the hybrid vehicle control ECU.
(b) Turn the ignition switch ON.
(c) Measure the voltage when these conditions are established.
Test conditions:
(1) Perform the ACTIVE TEST by using the Techstream.
(2) Operates the heater water pump.
(d) Measure the voltage according to the value(s) in the table below.
Voltage:

NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- Continue to next step.
9. INSPECT HEATER WATER PUMP ASSEMBLY
(a) Remove the heater water pump assembly.

(b) Disconnect the connector from the heater water pump assembly.
(c) 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.
NOTE: Complete operation within 10 seconds if there is no water in the heater water pump assembly.

NG -- REPLACE HEATER WATER PUMP ASSEMBLY
OK -- Continue to next step.
10. INSPECT J/B NO.2 (A/C W/P RELAY)
(a) Turn the ignition switch off.
(b) Remove the J/B No.2.

(c) Disconnect the connectors from the J/B No.2.
(d) 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).
(e) Measure the voltage according to the value(s) in the table below.
Voltage:

(f) Connect the positive (+) lead from the battery to terminal 2D-2 (WPB) and the negative (-) lead to terminals 2H-13 (SGND), 2F-1 (PGND) and 2H-10 (WP).
(g) Measure the voltage according to the value(s) in the table below.
Voltage:

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)

(a) Disconnect the connector from J/B No.2 (2D).
(b) Turn the ignition switch ON.
(c) Measure the voltage according to the value(s) in the table below.
Voltage:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
12. INSPECT J/B NO.2 (A/C W/P RELAY)
(a) Turn the ignition switch off.
(b) Remove the J/B No.2.

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)