Toyota Yaris: Air Conditioning System / Recirculated/Fresh Air Modes Switch without User Input

Toyota Yaris XP210 (2020-2024) Reapir and Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System / 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)

PROCEDURE

1.

CHECK CUSTOMIZE SETTING (EFFICIENT VENTILATION MODE)

(a) Using the GTS, check that the customize setting Efficient Ventilation Mode is not set to "ON".

Air Conditioner

Tester Display

Description

Default

Setting

ECU

Efficient Ventilation Mode

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

ON

$00:OFF,$01:ON

Air conditioning amplifier assembly

OK:

Efficient Ventilation Mode is not set to "ON".

NG

CUSTOMIZE SETTING

OK

2.

READ VALUE USING GTS (AMBIENT TEMPERATURE SENSOR)

(a) Read the Data List according to the display on the GTS.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Ambient Temperature Sensor

Thermistor assembly

Min.: -327.68°C (-557.82°F)

Max.: 327.67°C (621.81°F)

Actual ambient temperature displayed

Thermistor assembly circuit malfunction

Body Electrical > Air Conditioner > Data List

Tester Display

Ambient Temperature Sensor

OK:

The value of the display does not change frequently.

NG

GO TO AMBIENT TEMPERATURE DISPLAY SYSTEM

OK

3.

READ VALUE USING GTS (COOLANT TEMPERATURE)

(a) Read the Data List according to the display on the GTS.

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

4.

CHECK REFRIGERANT PRESSURE

(a) Read the Data List according to the display on the GTS.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Regulator Pressure Sensor

Air conditioner pressure sensor

Min.: -32.768 MPaG

Max.: 32.767 MPaG

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

(b) Install a manifold gauge set.

(c) 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)

(d) 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

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