Lexus NX: A/C Inverter Load System Malfunction (B1476)

DESCRIPTION

The operation of the compressor with motor assembly is stopped and this DTC is stored if the rotation load is too large or too small while the compressor with motor assembly is operating.

Possible causes are refrigerant leaks, overcharged refrigerant, insufficient cooling due to a condenser fan circuit malfunction, or compressor lock.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

Note

B1476

A/C Inverter Load System Malfunction

Motor rotation load while the compressor is operating is too large or too small

  • Refrigerant volume
  • Compressor with motor assembly
  • Cooling fan system
  • CAN communication system

Memorized

-

CAUTION / NOTICE / HINT

CAUTION:

  • Wear insulated gloves and pull out the service plug grip before inspection as procedures may require disconnecting high-voltage connectors. Carry the removed service plug in your pocket to prevent other technicians from accidentally reconnecting it while you are servicing the vehicle.
  • Do not touch the high-voltage connectors or terminals for 10 minutes after the service plug grip is removed.

NOTICE:

  • After the power switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

    Click here

  • When disconnecting and reconnecting the auxiliary battery terminal

    Click here

    HINT:

    When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

    Click here

  • The hybrid control system and air conditioning system output DTCs separately. Perform troubleshooting for the hybrid control system first if DTCs from these systems are output simultaneously.

PROCEDURE

1.

CHECK CAN COMMUNICATION SYSTEM

(a) Using the Techstream, check if the CAN communication system is functioning normally.

Click here

Result

Proceed to

CAN communication system DTCs are not output

A

CAN communication system DTCs are output

B

B

GO TO CAN COMMUNICATION SYSTEM

A

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: Powertrain / Engine and ECT / Active Test.

(e) Check the operation by referring to the table below.

Powertrain > Engine and ECT > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Control the Electric Cooling Fan

Control electric cooling fan motor

ON/OFF

Perform this test when the following conditions are met:

  • Power switch on (IG)
  • Engine stopped
  • Shift lever in P
Powertrain > Engine and ECT > Active Test

Tester Display

Control the Electric Cooling Fan

NG

GO TO COOLING FAN SYSTEM

OK

3.

CHECK REFRIGERANT PRESSURE

(a) Install a manifold gauge set.

Click here

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

(c) Read the manifold gauge pressure when the following conditions are met.

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

Item

Condition

Vehicle doors

Fully open

Temperature setting

MAX COLD

Blower speed

HI

A/C switch

On

Recirculation/fresh switch

RECIRCULATION

Interior temperature

25 to 35°C (77 to 95°F)

*a

LO

*b

HI

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)

OK

REPLACE COMPRESSOR WITH MOTOR ASSEMBLY

NG

CHARGE REFRIGERANT

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SEE MORE:

 Installation

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