COMBUSTION TYPE POWER HEATER SYSTEM Power Heater Fuel Pump Circuit

DESCRIPTION

When the power heater switch is turned on, the heater pump assembly receives a drive voltage from the heater assembly (ECU). The heater pump assembly provides the heater assembly with fuel necessary for combustion, allowing the heater assembly to operate.

WIRING DIAGRAM

A002NC0E03
*a Heater Pump Assembly
*b Heater Assembly

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (HEATER ASSEMBLY - HEATER PUMP ASSEMBLY AND BODY GROUND)


    1. A002PUQE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Heater Assembly)
      *2

      Front view of wire harness connector

      (to Heater Pump Assembly)

      Disconnect the A41 heater connector.

    2. Disconnect the A42 pump connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A41-2 (L) - A42-1 (B2) Always Below 1 Ω
      A42-2 (E2) - Body ground Always Below 1 Ω
      A41-2 (L) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT HEATER PUMP ASSEMBLY


    1. A002QXGE08

      Remove the heater pump assembly with the fuel hose still connected Click here.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (B2) - 2 (E2) Always 9 to 12 Ω

    3. Apply battery voltage to the heater pump assembly and check the pressure of the hose by hand.

      OK
      Measurement Condition Specified Condition

      Battery positive (+) → Terminal 1

      Battery negative (-) → Terminal 2

      		 Pressure is applied to the hose

      Note


      • This inspection must be done quickly (within 10 seconds) to prevent damage to the heater pump assembly.

      • Always switch the voltage on and off on the battery side, not the heater pump assembly side.

      • Keep the heater pump assembly as far away from the battery as possible.


    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

    REPLACE HEATER PUMP ASSEMBLY Click here