Heater Water Pump Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM: Heater Water Pump Circuit

Heater Water Pump Circuit

DESCRIPTION

The heater water pump sends engine coolant to the heater core while the engine is stopped to prevent heater effectiveness from becoming low.
Directed by the air conditioning amplifier, hybrid control ECU operates the water pump relay and drives the heater water pump.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT INTEGRATION RELAY (UNIT C: AC W/P)




(a) Remove the integration relay from the engine room junction block.
NOTE: As the integration relay is connected to the relays and fuses in the other systems, remove it with the power switch OFF. (A DTC may be output if the power switch is ON (IG).
(b) Measure the resistance of the relay.
Standard resistance:






NG -- REPLACE INTEGRATION RELAY
OK -- Continue to next step.

2. CHECK WIRE HARNESS (HYBRID CONTROL ECU - BATTERY)




(a) Install the integration relay.
(b) Disconnect the H16 ECU connectors.
Measure the voltage of the wire harness side connector.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

3. CHECK HYBRID CONTROL ECU (WP VOLTAGE)




(a) Measure the voltage of the connector.
Standard voltage:






NG -- REPLACE HYBRID CONTROL ECU
OK -- Continue to next step.

4. INSPECT HEATER WATER PUMP ASSEMBLY




(a) Remove the heater water pump.
(b) Connect positive (+) lead to terminal 1 of the heater water pump connector and negative (-) lead to terminal 2.
OK:
Heater water pump operates smoothly.
NOTE: Complete operation within 10 seconds if there is no water in the heater water pump.

NG -- REPLACE HEATER WATER PUMP ASSEMBLY
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR