Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001H97T
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 09/2022]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): Cooling is Poor; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

Cooling is Poor

DESCRIPTION

If the cooling effect of the air conditioning system is weak, the following factors may be the cause.

Symptom

Factor
  • Cooling effectiveness is poor
  • Cooling response is slow
  • ECO drive mode function (air flow volume is restricted due to ECO drive mode being selected)
  • Compressor with motor assembly malfunction
  • Refrigerant volume (high)
  • Refrigerant volume (low)
  • Clogged cooler condenser assembly fins
  • Cooling fan system malfunction
  • Mechanical locking of damper and damper link
  • Automatic light control sensor malfunction
  • High inlet air temperature
  • Harness or connector

PROCEDURE

1.

CHECK FOR DTC

(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 / Main Body / Trouble Codes.

(e) Check for DTCs.

Body Electrical > Main Body > Trouble Codes

Result

Proceed to

B1244 is not output

A

B1244 is output

B
B

GO TO DTC B1244

A

2.

CHECK ECO MODE SETTING

(a) Check if the ECO mode indicator is off.

OK:

The ECO mode indicator is off.

NG

GO TO STEP 4

OK

3.

CHECK ECO MODE CONTROL OPERATION

(a) Operate the ECO switch assembly (air conditioning control assembly) and check that the ECO mode indicator turns off and the blower speed reduction is canceled.

HINT:

  • When ECO mode control is operating, the air conditioning amplifier assembly controls the air conditioning system to enhance fuel efficiency. Therefore, explain to the customer that, when ECO mode control is operating, the blower speed will be reduced.

    Control

    Outline

    Blower Control

    When the air conditioning system is in AUTO mode, the blower speed will be reduced to a certain speed. Additionally, if warm-up control is operating, the blower speed will be further reduced.

    Air Inlet Control

    If the ambient temperature is a certain value or more, the air inlet mode will be changed to recirculation mode.
  • In some situations, ECO mode control may not operate even though it is enabled.

Result

Proceed to

ECO mode indicator turns off and blower speed reduction is canceled

A

ECO mode indicator turns off, but the blower speed reduction is not canceled

B

ECO mode indicator does not turn off

C
B

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

C

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

A

4.

PERFORM REFRIGERANT SHORTAGE CHECK

(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 / Utility / Refrigerant Gas Volume Check.

Body Electrical > Air Conditioner > Utility

Tester Display

Refrigerant Gas Volume Check

(e) Check that the following conditions are met and perform the refrigerant shortage check according to the display on the Techstream.

Measurement Condition:

Item

Condition

A/C switch

On

Ambient temperature*

0 to 49°C (32 to 120°F)

Blower speed

HI

*: If the ambient temperature is not within the range shown, do not perform this check.

Result

Amount of Refrigerant

Refrigerant correct

Correct

Refrigerant shortage

Insufficient

OK:

"Refrigerant correct" is displayed on the Techstream.

NG

REPAIR REFRIGERANT LEAK

for HFC-134a (R134a): Click here 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]; HEATING / AIR CONDITIONING: REFRIGERANT (for HFC-134a(R134a)): REPLACEMENT

for HFO-1234yf (R1234yf): Click here 2020 - 2021 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 06/2020]; HEATING / AIR CONDITIONING: REFRIGERANT (for HFO-1234yf(R1234yf)): REPLACEMENT 2021 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2020 -        ]; HEATING / AIR CONDITIONING: REFRIGERANT (for HFO-1234yf(R1234yf)): REPLACEMENT

OK

5.

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.

OK

INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET

for HFC-134a (R134a): Click here 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]; HEATING / AIR CONDITIONING: REFRIGERANT (for HFC-134a(R134a)): ON-VEHICLE INSPECTION

for HFO-1234yf (R1234yf): Click here 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]; HEATING / AIR CONDITIONING: REFRIGERANT (for HFO-1234yf(R1234yf)): ON-VEHICLE INSPECTION

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