Toyota Yaris: Air Conditioning System / Operation not Accepted Even If Air Conditioning Switch is Operated

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System / Operation not Accepted Even If Air Conditioning Switch is Operated

DESCRIPTION

If the air conditioning system cannot be operated using the air conditioning control assembly, the following factors may be the cause.

Symptom	Factor
Air conditioning system cannot be operated using air conditioning control assembly (With the exception of the switch indicators, no inputs are reflected when other switches operated)	LIN communication malfunction between air conditioning amplifier assembly and air conditioning control assembly Short to +B or ground in air conditioning amplifier assembly circuit Air conditioning amplifier assembly malfunction Air conditioning control assembly malfunction Harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.	CHECK FOR DTC

(a) Clear the DTCs.

Body Electrical > Air Conditioner > Clear DTCs

(b) Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
B14B287 is not output	A
B14B287 is output	B

GO TO DTC B14B287

2.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - POWER SOURCE AND BODY GROUND)

(a) Disconnect the air conditioning amplifier assembly connector.

(b) Measure the voltage and resistance according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Condition	Specified Condition
H24-5 (B) - Body ground	Always	11 to 14 V
H24-6 (IG+) - Body ground	Ignition switch ON	11 to 14 V
H24-6 (IG+) - Body ground	Ignition switch off	Below 1 V

Standard Resistance:

Tester Connection	Condition	Specified Condition
H24-17 (GND) - Body ground	Always	Below 1 Ω

*a	Front view of wire harness connector (to Air Conditioning Amplifier Assembly)

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

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 pulley 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 PROCEDURE 1...

Front Window Fogging

DESCRIPTION If the windshield frequently fogs up even though the air conditioning system is operating, the following factors may be the cause. Symptom Factor Windshield frequently fogs up Compressor malfunction Refrigerant volume (low) Cooler expansion valve (opened excessively) No...

Other information:

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual: On-vehicle Inspection

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Toyota Yaris XP210 (2020-2025) Reapir and Service Manual: Diagnostic Trouble Code Chart

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