STOP AND START SYSTEM Cooler Thermistor Circuit

DESCRIPTION

Stop and Start system control may be prohibited due to air conditioning system operation conditions. The prohibition conditions are shown in the table below.

System Prohibition Control due to Air Conditioning Operation Conditions
Prohibition Condition Effect without Restart Restoration Condition Prohibition Condition Check Timing

Heater:

All of the following conditions have been met:


  • Blower switch is ON

  • Outside temperature is 10°C (50°F) or less

  • Coolant temperature is less than 55 (131°F )

 Heater function is not effective

  • Blower switch is turned off

  • Coolant temperature is 55°C (131°F) or more:

 During heater operation

Cooling function:

All of the following conditions have been met:


  • Blower switch is ON

  • A/C switch is on

  • Outside temperature is 25°C (77°F) or more

  • Evaporator temperature is 8°C (46.4°F) or more (Once the temperature drops below 8°C (46.4°F) after the ignition switch is turned to ON, Stop and Start system control will be restored)

 Cooling function is not effective

Any of the following conditions have been met


  • Evaporator temperature is 8°C (46.4°F) or less

  • Blower switch is turned off

  • A/C is turned off

 While A/C (cooling function) is on

Defogger:

All of the following conditions have been met:


  1. The defogger switch is on and the blower switch is on (only for automatic air conditioners)

  2. For 10 seconds after restarting the engine by stop and start control, when the outside temperature is 10°C (50°F) or lower and the blower switch is on.

  3. For 30 seconds after restarting the engine by stop and start control, when the outside temperature is -7°C (19.4°F) or higher, the air conditioning switch is on, and the blower switch is on.

 Windows are easily fogged

The corresponding condition has been met:


  1. The defogger switch is off and the blower switch is off (only for automatic air conditioners)

  2. 10 seconds have passed after restarting the engine by the stop and start control or the blower switch is off.

  3. 30 seconds have passed after restarting the engine by the stop and start control or the air conditioning system is turned off or the blower switch is off.

 While A/C (cooling function for defogger) is on

WIRING DIAGRAM

A01VKQKE01
*a Cooler Thermistor
*b Engine Stop and Start ECU

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (A/C OUTLET TEMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Stop and Start / Data List / A/C Outlet Temp.

    5. Read the value when the A/C temperature switch is operated (HOT to COOL).

      OK
      Tester display value changes when the A/C switch is operated.

      Tech Tips

      The A/C Outlet Temp item in the Data List indicates the A/C blower temperature. Leaving the vehicle for an entire day allows the A/C Outlet Temperature value to equal the ambient temperature. While the ambient temperature is indicated in the Data List, check for changes in the outlet temperature by hand. If temperature changes cannot be felt, inspect the air conditioning system.


    OK

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

    NG

  2. INSPECT COOLER THERMISTOR


    1. Inspect the cooler thermistor Click here.


    NG

    REPLACE COOLER THERMISTOR Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - COOLER THERMISTOR)


    1. Disconnect the F31 cooler thermistor connector.

    2. Disconnect the A53 and F75 engine stop and start ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F75-23 (TFAL) - F31-1 (TFAR) Always Below 1 Ω
      A53-19 (BRE2) - F31-2 (SG) Always Below 1 Ω
      F31-1 (TFAR) or F75-23 (TFAL) - Body ground Always 10 kΩ or higher
      F31-2 (SG) or A53-19 (BRE2) - Body ground Always 10 kΩ or higher

    4. Reconnect the F31 cooler thermistor connector.

    5. Reconnect the A53 engine stop and start ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BODY GROUND)


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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F75-6 (GND) - Body ground Always Below 1 Ω
      F75-5 (GND2) - Body ground Always Below 1 Ω

    2. Reconnect the F75 engine stop and start ECU connector.


    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR