Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000026Z4H
Model Year Start: 2023 Model: Corolla Prod Date Range: [09/2022 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): Cooling is Poor; 2023 - 2025 MY Corolla Corolla HV [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 mode control of air conditioning system is enabled
  • 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
  • Solar sensor (automatic light control sensor) malfunction
  • High inlet air temperature
  • Harness or connector

WIRING DIAGRAM

PROCEDURE

1.

CHECK ECO MODE SETTING

(a) Confirm that ECO HEAT/COOL switch (air conditioning control assembly) is set to off.

(b) Confirm that ECO drive mode is set to off.

HINT:

When the ECO drive mode is set to ON, the air conditioning amplifier assembly performs minimal air conditioning control in order to promote the improvement of fuel economy. Ensure that the customer understands that the airflow volume will be decreased compared to normal operation.

Control

Control Summary

Air Volume Control

Sets the blower level to less.
NEXT

2.

CHECK REFRIGERANT SHORTAGE

(a) Prepare the vehicle according to the table below.

Measurement Condition:

Item

Condition

A/C Switch

On

Ambient Temperature*1

0 to 49°C (32 to 120°F)

Air Conditioning Air Inlet Temperature*2

25 to 35°C (77 to 95°F)

Set Temperature

MAX COLD

Recirculation/fresh Control Switch

Recirculation

Air Vent Damper Position

FACE

Blower Speed

HI

HINT:

*1: This inspection can be judged correctly only if the ambient temperature is within a range of 0 to 49°C (32 to 120°F). Therefore, postpone the test if the temperature is low.

*2: This inspection can be judged correctly only if the air inlet temperature is within a range of 25 to 35°C (77 to 95°F). Therefore, postpone the test if the temperature is out of range.

(b) Using the GTS, check the amount of refrigerant.

Body Electrical > Air Conditioner > Utility

Tester Display

Refrigerant Gas Volume Check

NOTICE:

If the conditions for the inspection are not met, "Refrigerant incorrect" will be displayed on the GTS. Confirm the conditions of the inspection and perform the check again.

HINT:

  • If the amount of refrigerant is insufficient, "Refrigerant shortage" is displayed on the GTS and the indicator light on the A/C switch turns off.
  • When performing this inspection, a DTC will not be output even if "Refrigerant shortage" is displayed on the GTS.

Result

Amount of Refrigerant

Refrigerant shortage

Insufficient or leakage

Refrigerant correct

Correct

Refrigerant incorrect

Incorrect

OK:

"Refrigerant correct" is displayed on the GTS.

NG

CHARGE SYSTEM WITH REFRIGERANT

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OK

3.

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.

NG

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

OK

4.

CHECK HARNESS AND CONNECTOR (SOLAR SENSOR (AUTOMATIC LIGHT CONTROL SENSOR) - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(a) Disconnect the h1 solar sensor (automatic light control sensor) connector.

(b) Disconnect the I85 main body ECU (multiplex network body ECU) connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

h1-1 (CLTB) - I85-8 (CLTB)

Always

Below 1 Ω

h1-2 (CLTE) - I85-21 (CLTE)

Always

Below 1 Ω

h1-4 (CLTS) - I85-20 (CLTS)

Always

Below 1 Ω

h1-1 (CLTB) or I85-8 (CLTB) - Other terminals and body ground

Always

10 kΩ or higher

h1-2 (CLTE) or I85-21 (CLTE) - Other terminals and body ground

Always

10 kΩ or higher

h1-4 (CLTS) or I85-20 (CLTS) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

INSPECT SOLAR SENSOR (AUTOMATIC LIGHT CONTROL SENSOR)

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OK

INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET

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NG

REPLACE SOLAR SENSOR (AUTOMATIC LIGHT CONTROL SENSOR)