Heater Water Pump Circuit

AIR CONDITIONING: 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 DTC (CAN COMMUNICATION SYSTEM)
(a) Use the Techstream to 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 (WATER PUMP RELAY)
(a) Select the Active Test, using the Techstream to generate a control command, and then check that the heater water pump operates.

Air Conditioner





Result





B -- INSPECT FUSE (A/C W/P, E/G R/M-IG1-1)
A -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3. INSPECT FUSE (A/C W/P, E/G R/M-IG1-1)
(a) Remove the A/C W/P and E/G R/M-IG1-1 fuses from the engine room No. 2 relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FUSE
OK -- Continue to next step.
4.
CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 JUNCTION BLOCK - BODY GROUND)




(a) Disconnect the 2G and 2F engine room No. 2 junction block connectors.
(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 ENGINE ROOM NO. 2 JUNCTION BLOCK




HINT: The A/C W/P relay is an inner circuit of the engine room No. 2 relay block.
(a) Remove the terminal cover from the engine room No. 2 junction block.
(b) Measure the voltage according to the value(s) in the table below for the A/C W/P relay terminal of the engine room No. 2 relay block.
Standard voltage:






NG -- REPLACE ENGINE ROOM NO. 2 JUNCTION BLOCK
OK -- Continue to next step.
6.
CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 JUNCTION BLOCK - HYBRID VEHICLE CONTROL)




(a) Disconnect the 2G engine room No. 2 junction block connector.
(b) Disconnect the A75 hybrid vehicle control ECU connector.
(c) 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.
7.
CHECK HARNESS AND CONNECTOR (HEATER WATER PUMP ASSEMBLY - BODY GROUND)




(a) Disconnect the A79 heater water pump assembly connector.
(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.
8.
CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 J/B - HEATER WATER PUMP ASSEMBLY)




(a) Disconnect the 2C engine room No. 2 junction block connector.
(b) Disconnect the A79 heater water pump assembly connector.
(c) 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.
INSPECT HEATER WATER PUMP ASSEMBLY




(a) Disconnect the A79 heater water pump assembly connector.
(b) Apply battery voltage to the terminals of the connector, and check the heater water pump operation.
OK:





NOTICE:
Complete this inspection 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. REPLACE AIR CONDITIONING AMPLIFIER
(a) Replace the air conditioning amplifier with a normal one and check that the condition returns to normal Removal.
OK:
Same problem does not occur.
NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- END (AIR CONDITIONING AMPLIFIER IS DEFECTIVE)