Heater Water Pump Circuit

HEATING / 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 assembly, the power management control ECU operates the water pump relay and drives the heater water pump assembly.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM

(a) Use the Techstream to check if the CAN communication system is functioning normally.

Result:





B -- GO TO CAN COMMUNICATION SYSTEM Diagnosis 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).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test.

(e) Check the operation by referring to the table below.

Air Conditioner





Result:





C -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

B -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
A -- Continue to next step.

3. INSPECT RELAY (A/C W/P)

(a) Remove the A/C W/P relay from the No. 1 engine room relay 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 (A/C FUSE - A/C W/P RELAY)

(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.

5. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU CIRCUIT)

(a) Reinstall the A/C W/P relay to the HV SUB relay block and junction block 2.

(b) Disconnect the connector from the power management control ECU.

(c) 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. CHECK HARNESS AND CONNECTOR (A/C W/P RELAY CIRCUIT)

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





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

Standard Voltage:





Text in Illustration





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

7. INSPECT HEATER WATER PUMP ASSEMBLY

(a) Disconnect the connector from the heater water pump assembly.

(b) Connect the positive (+) lead from a battery to terminal 2 and the negative (-) lead to terminal 1.





OK:

Heater water pump assembly operates smoothly.

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

Text in Illustration





NG -- REPLACE HEATER WATER PUMP ASSEMBLY Removal
OK -- Continue to next step.

8. 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.

9. CHECK HARNESS AND CONNECTOR (HEATER WATER PUMP ASSEMBLY - ENGINE R/B AND J/B)

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

10. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Replace the air conditioning amplifier assembly with a known good one and check if the same problem occurs again Removal.

OK:

Same problem does not occur.

NG -- REPLACE POWER MANAGEMENT CONTROL ECU Removal

OK -- END (AIR CONDITIONING AMPLIFIER ASSEMBLY WAS DEFECTIVE)