Heater Water Pump Circuit

AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Manual 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, the hybrid vehicle control ECU operates the water pump relay and drives the heater water pump assembly.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM
(a) Using the Techstream, check if the CAN communication system is functioning normally.
Result:






B -- GO TO CAN COMMUNICATION SYSTEM
A -- Continue to next step.
2. PERFORM ACTIVE TEST USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the Techstream on.
(c) Select the item below in the Active Test and check that the relay operates.

Active Test / Air Conditioner:





OK:
Heater water pump operates smoothly.
NG -- INSPECT RELAY (A/C W/P)
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3. INSPECT RELAY (A/C W/P)





(a) Remove the A/C W/P relay from the engine room relay block and No. 1 junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE RELAY (A/C W/P)
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BATTERY)





(a) Disconnect the connector from the hybrid vehicle control ECU.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (BATTERY - ENGINE ROOM R/B AND J/B NO. 1)





(a) Remove the A/C W/P relay from the engine room relay block and No. 1 junction block.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






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





(b) Connect a positive (+) lead from the battery to terminal 1 and a negative (-) lead to terminal 2.
OK:
Heater water pump operates smoothly.
NOTE: Complete this inspection within 5 seconds if there is no water in the heater water pump assembly.

NG -- REPLACE HEATER WATER PUMP ASSEMBLY
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (HEATER WATER PUMP ASSEMBLY - BODY GROUND)





(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (HEATER WATER PUMP ASSEMBLY - ENGINE ROOM R/B AND J/B NO. 1)





(a) Remove the A/C W/P relay from the engine room relay block and No. 1 junction block.





(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. REPLACE AIR CONDITIONING AMPLIFIER
(a) Replace the air conditioning amplifier with a normal one and check if the same problem occurs again.
OK:
Same problem does not occur.
NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- END