DTC B1474-4B: A/C Inverter Cooling/Heating Over Temperature [09/2022 - ]: Procedure

1. Perform the Active Test according to the display on the GTS.

   Powertrain > Engine > Active Test 

   Tester Display	Measurement Item	Control Range	Restrict Condition
   Control the Engine Cooling Fan	Control electric cooling fan motor	OFF/Low/High	Perform this test when vehicle is stopped.

   Powertrain > Engine > Active Test 

   Tester Display
   Control the Engine Cooling Fan

   OK

   Electric cooling fan operates smoothly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

GO TO COOLING FAN SYSTEM. Refer to  ON-VEHICLE INSPECTION [01/2019 - ] 

Result: 

OK 

See step  2

1. Install a manifold gauge set.

   for HFC-134a (R134a): Refer to ON-VEHICLE INSPECTION [01/2019 - ]

   for HFO-1234yf (R1234yf): Refer to ON-VEHICLE INSPECTION [01/2019 - ]

2. Prepare the vehicle according to the table below.
   MEASUREMENT CONDITION:
   
   

   Item	Condition
   Doors	Fully open
   A/C Switch	On
   Recirculation/fresh Control Switch	Recirculation
   Set Temperature	MAX COLD
   Blower Speed	HI
   Air Conditioning Air Inlet Temperature	25 to 35°C (77 to 95°F)

3. Read the manifold gauge pressure.

   Standard Pressure

   Low pressure side 

   150 to 250 kPa (1.5 to 2.5 kgf/cm² , 22 to 36 psi)

   High pressure side 

   1370 to 1570 kPa (14 to 16 kgf/cm² , 199 to 228 psi)

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CHARGE REFRIGERANT 

for HFC-134a (R134a): Refer to REPLACEMENT [01/2019 - ]

for HFO-1234yf (R1234yf): Refer to REPLACEMENT [06/2020 - ]

Result: 

OK 

See step  3

1. Clear the DTCs.

   Body Electrical > Air Conditioner > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  4

1. Set the vehicle condition when the DTCs are output.
   1. Set the "Inspection Mode".

      Refer to INSPECTION MODE PROCEDURE [06/2018 - ]

   2. Prepare the vehicle according to the table below for 30 minutes or more.

      Item	Condition
      Blower Speed	HI
      A/C Switch	On
      Set Temperature	MAX COLD

2. Check for DTCs.

   Body Electrical > Air Conditioner > Trouble Codes 

   NOTE:

   If the engine keeps idling when the ambient temperature is high, the compressor with motor assembly may automatically stop to protect the inverter circuit, and DTC B1474-4B may be stored.

   Result

   Result	Proceed to
   DTC B1474-4B is not output	A
   DTC B1474-4B is output	B

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ] 

Result: 

B 

REPLACE COMPRESSOR WITH MOTOR ASSEMBLY. Refer to  REMOVAL [09/2022 - 11/2022]  , or refer to  REMOVAL [11/2022 - ]