Inspection Procedure

WARNING: This page is about a different car, the 2009 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Turn the ignition switch off before measuring the resistance of the 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 DTC

Check the 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 REFERENCE

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

B: GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A: Go to Next Step

CHECK CAN MS BUS WIRE (CERTIFICATION ECU)

Turn the ignition switch off.
Disconnect the certification ECU connector from the certification ECU.
Measure the resistance according to the value (s) in the table below.

Standard Resistance

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
E36-27 (CANH) - E36-28 (CANL)	Ignition switch off	54 to 69 Ω

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

Fig 1: Identifying E36 Certification ECU Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Condition	Specified Condition
E36-17 (E) - Body ground	Always	Below 1 Ω

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

Standard Voltage

STANDARD VOLTAGE SPECIFICATION

Tester Connection	Condition	Specified Condition
E36-18 (IG) - Body ground	Ignition switch ON	10 to 14 V
E36-1 (+B) - Body ground	Always	10 to 14 V
E36-19 (ACC) - Body ground	Ignition switch ACC	10 to 14 V

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 2: Identifying E36 Certification ECU Connector

OK: REPLACE CERTIFICATION ECU