Toyota Yaris: Air Conditioning System / No Warm Air Comes Out

Toyota Yaris XP210 (2020-2026) Reapir and Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System / No Warm Air Comes Out

DESCRIPTION

If cool air blows from the registers regardless of the temperature setting of the air conditioning system, the following factors may be the cause.

Symptom

Factor
  • No warm air comes out

    (Blower control is normal)

  • Outlet air temperature does not increase

    (Blower control is normal)
  • Flow shutting valve malfunction
  • Engine coolant temperature (low)
  • No. 1 air conditioning radiator damper servo sub-assembly malfunction
  • Damper and damper link
  • Warm-up control
  • Blockage in heater radiator unit sub-assembly
  • Heater radiator unit sub-assembly malfunction

PROCEDURE

1.

CHECK FOR DTC

(a) Check for DTCs.

Powertrain > Engine > Trouble Codes

OK:

SFI system DTCs are not output.

NG

GO TO SFI SYSTEM

OK

2.

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:

After warming up the engine, the temperature value displayed is within the range specified in the normal condition column.

NG

GO TO COOLING SYSTEM

OK

3.

PERFORM ACTIVE TEST USING GTS (FRONT LEFT AIR MIX DAMPER CONTROL SERVO MOTOR, FRONT RIGHT AIR MIX DAMPER CONTROL SERVO MOTOR)

(a) Perform the Active Test according to the display on the GTS.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Front Left Air Mix Damper Control Servo Motor

No. 1 air conditioning radiator damper servo sub-assembly pulse

Min.: 128

Max.: 384

-

Front Right Air Mix Damper Control Servo Motor

No. 1 air conditioning radiator damper servo sub-assembly pulse

Min.: 128

Max.: 384

-
Body Electrical > Air Conditioner > Active Test

Tester Display

Front Left Air Mix Damper Control Servo Motor
Body Electrical > Air Conditioner > Active Test

Tester Display

Front Right Air Mix Damper Control Servo Motor

OK:

Each damper servo motor operates.

OK

REPLACE HEATER RADIATOR UNIT SUB-ASSEMBLY

NG

GO TO DTC TROUBLESHOOTING PROCEDURE FOR MALFUNCTIONING DAMPER SERVO MOTOR

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