Inspection Procedure

NOTE:

Turn the ignition switch off before measuring the resistance of CAN bus main wires and the CAN bus branch wires.
After the ignition switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.
Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors. If any doors need to be opened in order to check the connectors, open the doors and leave them open.

HINT:

Operating the ignition switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below will help determine the cause of the malfunction.

CHECK CAN BUS LINE FOR DISCONNECTION (NETWORK GATEWAY ECU BRANCH WIRE)

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

Standard Resistance

RESISTANCE SPECIFIED CONDITIONS

Tester Connection	Switch Condition	Specified Condition
E53-16 (CA1H) - E53-15 (CA1L)	Ignition switch off	54 to 69 Ω

Fig 1: Identifying Network Gateway ECU (E53) Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO NETWORK GATEWAY ECU (CANH, CANL)

OK: Go to Next Step

CHECK WIRE HARNESS (NETWORK GATEWAY ECU - BATTERY AND BODY GROUND)

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

Standard Resistance

RESISTANCE SPECIFIED CONDITIONS

Tester Connection	Condition	Specified Condition
E53-4 (GND) - Body ground	Always	Below 1 Ω

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

Standard Voltage

VOLTAGE SPECIFIED CONDITIONS

Tester Connection	Switch Condition	Specified Condition
E53-10 (IG1) - Body ground	Ignition switch ON	10 to 14 V
E53-9 (IG2) - Body ground	Ignition switch ON	10 to 14 V

Fig 2: Identifying Network Gateway ECU (E53) Connector Terminals

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE NETWORK GATEWAY ECU (See REMOVAL )