Inspection Procedure

NOTE:

Turn the ignition switch off before measuring the resistances of CAN bus main wires and 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 THE VEHICLE TYPE

Result

RESULT

Result	Proceed to
w/ Power back door system	A
w/o Power back door system	B

A: Go to next step

CHECK FOR DTC

Check for DTC.

HINT:

If the CAN MS bus communication error DTC U1002 is output, troubleshoot for U1002 and check for malfunctions in the CAN MS main bus circuit (See DTC U1002 (CAN MS BUS) LOST COMMUNICATION WITH GATEWAY MODULE (MAIN BODY ECU) ).

Result

RESULT

Result	Proceed to
U1002 is not output	A
U1002 is output	B

A: Go to next step

CHECK CAN MS BUS WIRE (CERTIFICATION ECU)

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

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION TABLE

Tester Connection	Condition	Specified Condition
D40-27 (CANH) - D40-28 (CANL)	Ignition switch off	108 to 132 Ω

Fig 1: Identifying D40 Certification ECU Connector Terminals (1 Of 2)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE CAN MS BUS BRANCH WIRE OR CONNECTOR (CERTIFICATION ECU)

OK: Go to next step

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

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

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION TABLE

Tester Connection	Condition	Specified Condition
D40-17 (E) - Body ground	Always	Below 1 Ω

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

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION TABLE

Fig 2: Identifying D40 Certification ECU Connector Terminals (2 Of 2)

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE CERTIFICATION ECU