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 main CAN bus wires and the CAN Bus branch wire.
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 (MAIN BODY ECU BRANCH WIRE)

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

Standard Resistance:

w/ Smart Key System or Automatic Light Control System

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
E52-15 (CANH) - E52-16 (CANL)	Ignition switch off	54 to 69 Ω

w/o Smart Key and Start System or Automatic Light Control System

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
E61-23 (CANH) - E61-22 (CANL)	Ignition switch off	54 to 69 Ω

NG: REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (MAIN BODY ECU BRANCH WIRE)

Fig 1: Identifying E52 And E61 Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step

CHECK HARNESS AND CONNECTOR (BECU, IG, GND1)

Disconnect the instrument panel junction block connectors.

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

Standard Resistance

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Condition	Specified Condition
2E-17 (GND1) - 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
2B-30 (BECU) - Body ground	Always	10 to 14 V

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 2: Identifying 2E And 2B Instrument Panel Junction Block Connectors

OK: REPLACE INSTRUMENT PANEL JUNCTION BLOCK (MAIN BODY ECU)