Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000028C5K
Model Year Start: 2023 Model: GR Corolla Prod Date Range: [11/2022 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Manual Air Conditioning System): No Heating at All; 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]

No Heating at All

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)
  • Engine coolant temperature (low)
  • Air mix damper and link operation (jamming)
  • Warm-up control
  • Blockage in heater radiator unit sub-assembly
  • Heater radiator unit sub-assembly malfunction

PROCEDURE

1.

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

2.

PERFORM ACTIVE TEST USING GTS

(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 Air Mix Damper Control Servo Motor

This test activates the front air mix damper control servo motor.

(No. 1 air conditioning radiator damper servo sub-assembly (air mix))

128: Min

384: Max

Operate with the ignition switch ON.

Body Electrical > Air Conditioner > Active Test

Active Test Display

Front Air Mix Damper Control Servo Motor

Data List Display

Front Air Mix Damper Control Servo Motor Actual Pulse

OK:

Damper servo motor is operated.

OK

REPLACE HEATER RADIATOR UNIT SUB-ASSEMBLY

NG

GO TO DIAGNOSTIC TROUBLE CODE CHART (FOR SERVO MOTOR OF APPLICABLE ABNORMAL OPERATION)