Lexus NX manuals

Lexus NX: A/C Inverter Start-up Signal System Malfunction (B1473)

Lexus NX Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System / A/C Inverter Start-up Signal System Malfunction (B1473)

DESCRIPTION

The inverter activation signal is sent to the compressor with motor assembly from the hybrid vehicle control ECU. Compressor control is stopped and this DTC is stored if there is an open or short in the signal circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

Note

B1473

A/C Inverter Start-up Signal System Malfunction

Open or short in A/C inverter start-up signal system
  • Harness or connector between hybrid vehicle control ECU and compressor with motor assembly
  • Compressor with motor assembly
  • Hybrid vehicle control ECU
  • Hybrid control system
  • CAN communication system

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WIRING DIAGRAM

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.

CHECK FOR DTC

(a) Check if air conditioning system and hybrid control system DTCs are output.

Click here

Click here

Powertrain > Hybrid Control > Trouble Codes Body Electrical > Air Conditioner > Trouble Codes

Result

Proceed to

Only DTC B1473 is output

A

DTCs B1473 and P3108 are output simultaneously (B1498 is not output)

DTCs B1473 and B1498 are output simultaneously (P3108 is not output)

B

DTCs B1473, B1498 and P3108 are output simultaneously

DTCs other than P3108 are output for hybrid control system

C
B

GO TO DTC B1498

C

GO TO HYBRID CONTROL SYSTEM

A

3.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - COMPRESSOR WITH MOTOR ASSEMBLY)

CAUTION:

Do not disconnect the connector on the high-voltage side.

(a) Disconnect the A61 hybrid vehicle control ECU connector.

(b) Disconnect the C43 compressor with motor assembly connector.

NOTICE:

Do not allow any foreign matter or water to enter the compressor with motor assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A61-11 (STB) - C43-4 (STBI)

Always

Below 1 Ω

A61-11 (STB) or C43-4 (STBI) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

INSPECT COMPRESSOR WITH MOTOR ASSEMBLY

(a) Disconnect the hybrid vehicle control ECU connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A61-11 (STB) - Body ground

Power switch on (IG)

11 to 14 V

A61-11 (STB) - Body ground

Power switch off

Below 1 V

*a

Front view of wire harness connector

(to Hybrid Vehicle Control ECU)
OK

REPLACE HYBRID VEHICLE CONTROL ECU

NG

REPLACE COMPRESSOR WITH MOTOR ASSEMBLY

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