Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminals +B, ACC, IG and GND of network gateway ECU.

Disconnect the connector from the network gateway ECU.

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

Standard:

NETWORK GATEWAY ECU +B, ACC, IG AND GND TERMINALS VOLTAGE

Tester connection	Condition	Specified condition
BATT - GND	Always	10 to 14 V
ACC - GND	Ignition SW ACC	10 to 14 V
IG - GND	Ignition SW ON	10 to 14 V

Fig 1: Checking Voltage Between Terminals +B, ACC, IG And GND Of Network Gateway ECU

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Proceed to next circuit inspection shown in. (See PROBLEM SYMPTOMS TABLE )
NG

Check continuity between terminal GND of network gateway ECU and body ground.

Disconnect the connector from the network gateway ECU.

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

Standard:

NETWORK GATEWAY ECU GND TERMINAL AND BODY GROUND RESISTANCE

Tester connection	Condition	Specified condition
GND - Body ground	Always	Below 1 Ω

Fig 2: Checking Continuity Between Terminal GND Of Network Gateway ECU And Body Ground

OK: Repair or replace harness or connector between navigation ECU and fuse.
NG: Repair or replace harness or connector between navigation ECU and body ground.