COMBUSTION TYPE POWER HEATER SYSTEM Power Heater Alternator Circuit

DESCRIPTION

The power heater ECU receives engine operation signals from the power management control ECU. If this circuit is open, the power heater ECU will determine that engine operation signals indicate on. If this circuit is shorted, the power heater ECU will determine that engine operation signals indicate off and the power heater will not operate.

PROCEDURE

1. Click here

   CHECK HARNESS AND CONNECTOR (POWER HEATER ECU (COMBUSTION HEATER ASSEMBLY) - POWER MANAGEMENT CONTROL ECU)

   
   

   1. Disconnect the A29 power heater ECU (combustion heater assembly) connector.

   2. Disconnect the F74 power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A29-8 (+) - F74-10 (ALTL) Always Below 1 Ω A29-8 (+) - Body ground Always 10 kΩ or higher

   
   
   • OKClick here
   • NG

     REPAIR OR REPLACE HARNESS OR CONNECTOR

2. Click here

   CHECK HARNESS AND CONNECTOR (POWER HEATER ECU (COMBUSTION HEATER ASSEMBLY) - BATTERY)

   
   
   1. 

      Reconnect the power management control ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition A29-8 (+) - Body ground Engine idling (Generator: Operating) 11 to 14 V

      Table 2. Text in Illustration

      *a	Front view of wire harness connector (to Power Heater ECU (Combustion Heater Assembly))

   
   
   • OKClick here
   • NG

     REPAIR OR REPLACE HARNESS OR CONNECTOR

3. Click here

   CHECK CHARGING SYSTEM

   
   

   1. Check the charging system (Click here).

   
   
   • OK

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

   • NG

     GO TO CHARGING SYSTEM (Click here)