Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001A3KP
Model Year Start: 2019 Model: Avalon Prod Date Range: [04/2018 - 08/2020]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model): Recirculated/Fresh Air Modes Switch without User Input; 2019 - 2020 MY Avalon [04/2018 - 08/2020]

Recirculated/Fresh Air Modes Switch without User Input

DESCRIPTION

If recirculation/fresh mode changes unintentionally and without permission, the following causes are possible.

Symptom

Factor
  • Recirculation/fresh mode changes without permission
  • Recirculation/fresh mode light blinks
  • Customize setting*
  • Change in ambient air temperature
  • Decrease in refrigerant pressure
  • Air conditioner pressure sensor circuit malfunction
  • Engine coolant temperature (high)
  • *: except USA and Canada

PROCEDURE

1.

CONFIRM MODEL

Result

Proceed to

for USA and Canada

A

except USA and Canada

B
A

GO TO STEP 3

B

2.

CHECK CUSTOMIZE SETTING

(a) Using the Techstream, check that the customize setting Air Inlet Mode is not set to "Automatic".

Air Conditioner

Tester Display

Description

Default

Setting

ECU

Air Inlet Mode

Function to change the mode automatically to recirculation air mode when turning the A/C on to cool the cabin quickly

Automatic

0:Automatic,1:Manual

Air conditioning amplifier assembly

OK:

Air Inlet Mode is not set to "Automatic".

NG

CUSTOMIZE SETTING

Set Air Inlet Mode to "Manual"
OK

3.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Ambient Temp Sensor

Thermistor assembly

Min.: -23.30°C (-9.94°F)

Max.: 65.95°C (150.71°F)

Actual ambient temperature displayed

Thermistor assembly circuit malfunction

  • When open circuit: -23.30°C (-9.94°F)
  • When short circuit: 65.95°C (150.71°F)

Body Electrical > Air Conditioner > Data List

Tester Display

Ambient Temp Sensor

OK:

The value of the display does not change frequently.

NG

GO TO AMBIENT TEMPERATURE DISPLAY SYSTEM

OK

4.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List.

(e) Read the Data List according to the display on the Techstream.

Powertrain > Engine > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Coolant Temperature

Engine coolant temperature

Min.: -40°C (-40°F), Max.: 140°C (284°F)

75 to 100°C (167 to 212°F): After warming up

This is the engine coolant temperature.

HINT:

  • After warming up the engine, the engine coolant temperature will be 75 to 100°C (167 to 212°F).
  • After a long soak, the engine coolant temperature, intake air temperature and ambient air temperature will be approximately equal.
  • If the value is -40°C (-40°F), or higher than 135°C (275°F), the sensor circuit is open or shorted.
  • Check if the engine overheats if the value indicated is higher than 135°C (275°F).

Powertrain > Engine > Data List

Tester Display

Coolant Temperature

OK:

The value of the display does not change frequently.

NG

GO TO COOLING SYSTEM

OK

5.

CHECK REFRIGERANT PRESSURE

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Regulator Pressure Sensor

Air conditioner pressure sensor

Min.: -456.68 kPaG

Max.: 3294.37 kPaG

Actual refrigerant pressure displayed
  • Refrigerant line (gas leak etc.)
  • Air conditioner pressure sensor circuit malfunction

Body Electrical > Air Conditioner > Data List

Tester Display

Regulator Pressure Sensor

(f) Install a manifold gauge set.

(g) Read the manifold gauge pressure when the following conditions are met.

(1) Prepare the vehicle according to the table below.

Measurement Condition:

Item

Condition

Vehicle doors

Fully open

Temperature setting

MAX COLD

Blower speed

HI

A/C switch

On

Recirculation/fresh switch

RECIRCULATION

Interior temperature

25 to 35°C (77 to 95°F)

Standard Pressure:

Low pressure side

150 to 250 kPa (1.5 to 2.5 kgf/cm2, 22 to 36 psi)

High pressure side

1370 to 1570 kPa (14 to 16 kgf/cm2, 199 to 228 psi)

(h) Compare the values displayed in the Data List and on the manifold gauge.

OK:

The values displayed in the Data List and on the manifold gauge match.

OK

GO TO ON-VEHICLE INSPECTION (CHECK REFRIGERANT PRESSURE USING GAUGE)

NG

REPLACE AIR CONDITIONER PRESSURE SENSOR