DTC P162B-87: Lost Communication with Battery Monitor Module Missing Message [03/2023 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus NX 350, 2024 Lexus NX 350, 2023 Lexus NX 350, and 2022 Lexus NX 350. However, it is still accessible from the selected car via links, so may be relevant.

CHECK BATTERY STATE SENSOR ASSEMBLY INSTALLATION CONDITION

Check installation condition of the battery state sensor assembly.

Result

Proceed to
OK
NG

Result:

INSTALL THE BATTERY STATE SENSOR ASSEMBLY CORRECTLY. Refer to INSTALLATION [11/2021 - ]

Result:

See step 2

CHECK CHARGING SYSTEM
Refer to ON-VEHICLE INSPECTION [11/2021 - ]

Result

Proceed to

OK

NG

Result:

NG

REPAIR OR REPLACE CHARGING SYSTEM

Result:

OK

See step 3

CHECK HARNESS AND CONNECTOR (ECM - BATTERY STATE SENSOR ASSEMBLY)

Disconnect the ECM connector.
Disconnect the battery state sensor assembly connector.
Disconnect the generator assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
B51-44 (LIN) - A45-2 (LIN)	Always	Below 1 Ω
B51-44 (LIN), A45-2 (LIN) or B57-2 (LIN) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 4

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

Check that the battery state sensor assembly connector is securely connected.
OK

The connector is securely connected.
Disconnect the battery state sensor assembly connector.
Check the connector case and terminals for deformation or corrosion.
OK

No deformation or corrosion.

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

Standard Voltage

Tester Connection	Condition	Specified Condition
A45-3 (+B) - Body ground	Always	11 to 14 V

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 5

CLEAR DTC

Check for DTCs, and note down any DTCs that are output.
Powertrain > Engine > Trouble Codes
Clear the DTCs.
Powertrain > Engine > Clear DTCs

Turn the ignition switch off, wait 30 seconds.

Result

Proceed to
NEXT

Result:

See step 6

CHECK DTC OUTPUT

Start the engine.
Allow the engine to idle for approximately 60 seconds or more.

Check for DTCs.

Powertrain > Engine > Trouble Codes

Result

Result	Proceed to
Only DTC P162B-87 is output	A
DTC P161A-87 and P162B-87 are output.	B
DTCs are not output.	C

Result:

REPLACE BATTERY STATE SENSOR ASSEMBLY. Refer to REMOVAL [11/2021 - ]

Result:

REPLACE ECM. Refer to REMOVAL [11/2021 - ]

Result:

CHECK FOR INTERMITTENT PROBLEMS. Refer to CHECK FOR INTERMITTENT PROBLEMS [11/2021 - ]