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Heater Water Pump Circuit [12/2019 - ]: Description

The heater water pump assembly supplies engine coolant to the heater radiator unit sub-assembly to prevent a decrease in the effectiveness of the heater when the engine is stopped by the stop and start system.

According to signals from the air conditioning amplifier assembly, the engine stop and start ECU operates the heater water pump relay to operate the heater water pump assembly.

Malfunction Status Factor
  • No warm air comes out (Blower control is normal)
  • Outlet air temperature does not increase (Blower control is normal)
  • Temperature of outlet air is warmer on left or right side (When same temperature set for both sides)
  1. A/C W/PMP relay (air conditioning water pump relay) malfunction
  2. Heater water pump assembly malfunction
  3. Air conditioning amplifier assembly malfunction
  4. Engine stop and start ECU malfunction
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