Lighting. Dtc B2402 Transistor Relay Overload Malfunction

Body Electrical. Lexus Gs430, Gs300. Uzs190 Grs190

Lighting. Lexus Gs430, Gs300. Uzs190 Grs190

CHECK WIRE HARNESS (MULTIPLEX NETWORK REAR ECU)

DTC B2402 Transistor Relay Overload Malfunction

DESCRIPTION

The electric current flowing in the transistor inside the Junction Block is examined by the Multiplex Network Rear ECU (Luggage room Junction Block ECU).
When excessive current is detected, DTC B2402 is output.
When overheating occurs prior to an excessive current, the ECU cuts off the current in the transistor to prevent it from being damaged and outputs DTC B2403.
Normally, turning off the engine switch clears DTC.
However, if an excessive current is detected frequently (9 times or more), DTC may not be cleared.
When this happens, disconnect the cable from the negative (-) battery terminal to clear DTC.

DTC No.	DTC Detection Condition	Trouble Area
B2402	Transistor relay overload malfunction	Multiplex network rear ECU Wire harness or connector

HINT:

When "B2403" is output, "B2402" is also output.

INSPECTION PROCEDURE

1.READ VALUE OF INTELLIGENT TESTER

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG) and press the intelligent tester main switch on.

Select the items below in the Data List, and read the displays on the intelligent tester.

Multiplex network rear ECU
Item	Measurement Item / Display (Range)	Normal Condition	Diagnostic Note
Tail Light Tr	Taillight transistor / OK or BREAK	ON or OFF	-
Stop Light Tr	Stop light transistor transistor / OK or BREAK	ON or OFF	-
High Mount Stop Light Tr	High mount stop Light transistor / OK or BREAK	ON or BREAK	-
License light Tr	License light transistor / OK or BREAK	ON or BREAK	-

OK:: Condition sign can be displayed.

Go to step 2

NORMAL OPERATION, NOT A MALFUNCTION

2.CHECK WIRE HARNESS (MULTIPLEX NETWORK REAR ECU)

Check each circuit in the table below.

Suspected Area	See Page
Taillight	Click here
Stop light	Click here
Back-up light	Click here

OK:: Each light illuminates.

REPAIR OR REPLACE HARNESS AND CONNECTOR

REPLACE MULTIPLEX NETWORK REAR ECU