Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001H983
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 09/2022]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): No Warm Air Comes Out; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

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)
  • Engine coolant temperature (low)
  • No. 1 air conditioning radiator damper servo sub-assembly malfunction
  • Warm-up control
  • Blockage in heater radiator unit sub-assembly
  • Quick heater assembly malfunction*
  • Heater radiator unit sub-assembly malfunction
  • *: w/ PTC Heater

PROCEDURE

1.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power 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:

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

NG

GO TO COOLING SYSTEM 2020 MY Corolla Corolla HV [01/2019 - 04/2020]; 2ZR-FXE (COOLING): COOLING SYSTEM: ON-VEHICLE INSPECTION 2021 - 2025 MY Corolla Corolla HV [04/2020 -        ]; 2ZR-FXE (COOLING): COOLING SYSTEM: ON-VEHICLE INSPECTION

OK

2.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Air Mix Servo Targ Pulse(D)

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

Min.: 128

Max.: 383

Operates between 165 and 257 pulses

Body Electrical > Air Conditioner > Active Test

Tester Display

Air Mix Servo Targ Pulse(D)

OK:

The No. 1 air conditioning radiator damper servo motor operates.

NG

GO TO DTC TROUBLESHOOTING PROCEDURE FOR MALFUNCTIONING DAMPER SERVO MOTOR 2020 MY Corolla Corolla HV [01/2019 - 04/2020]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART 2021 - 2022 MY Corolla Corolla HV [04/2020 - 09/2022]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART

OK

3.

CONFIRM MODEL

(a) Choose the model to be inspected.

Result

Proceed to

w/ PTC Heater

A

w/o PTC Heater

B
B

REPLACE HEATER RADIATOR UNIT SUB-ASSEMBLY 2020 - 2021 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 06/2020]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT: DISASSEMBLY 2021 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2020 - 09/2022]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT: DISASSEMBLY

A

4.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test / Heater Active Level / Data List / Electric Heater Active Level.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Heater Active Level

Quick heater assembly

Min.: 0

Max.: 3

-

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Electric Heater Active Level

Actual electric heater operation level

Min.: 0

Max.: 3

Actual operation level of electric heater displayed

PTC heater circuit malfunction

Body Electrical > Air Conditioner > Active Test

Active Test Display

Heater Active Level

Data List Display

Electric Heater Active Level

(e) Check that the value of the Data List item Electric Heater Active Level changes in accordance with the set value of the Active Test item Heater Active Level.

OK:

Techstream Operation

Data List (Electric Heater Active Level)

0 to 3

0 to 3
OK

REPLACE HEATER RADIATOR UNIT SUB-ASSEMBLY 2020 - 2021 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 06/2020]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT: DISASSEMBLY 2021 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2020 - 09/2022]; HEATING / AIR CONDITIONING: AIR CONDITIONING UNIT: DISASSEMBLY

NG

GO TO PTC HEATER CIRCUIT