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 (AIR CONDITIONING AMPLIFIER BRANCH WIRE)

Turn the ignition switch off.
Disconnect the air conditioning amplifier connector.
Measure the resistance according to the value (s) in the table below.

Standard Resistance: Automatic Air Conditioning

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
E30-11 (CANH) - E30-12 (CANL)	Ignition switch off	54 to 69 Ω

Manual Air Conditioning

SWITCH CONDITION CHART

Tester Connection	Switch Condition	Specified Condition
E63-8 (CANH) - E63-9 (CANL)	Ignition switch off	54 to 69 Ω

NG: REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (AIR CONDITIONING AMPLIFIER BRANCH WIRE)

Fig 1: Identifying E30 Auto And E63 Manual Air Conditioning Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step

CHECK HARNESS AND CONNECTOR (IG+, GND)

Disconnect the air conditioning amplifier connector.

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

Standard Resistance: Automatic Air Conditioning

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Condition	Specified Condition
E30-14 (GND) - Body ground	Always	Below 1 Ω

Manual Air Conditioning

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Condition	Specified Condition
E63-24 (GND) - Body ground	Always	Below 1 Ω

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

Standard Voltage: Automatic Air Conditioning

STANDARD VOLTAGE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
E30-1 (IG+) - Body ground	Ignition switch ON	10 to 14 V

Manual Air Conditioning

STANDARD VOLTAGE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
E63-14 (IG+) - Body ground	Ignition switch ON	10 to 14 V

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 2: Identifying E30 Auto And E63 Manual Air Conditioning Connectors

OK: REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (See AIR CONDITIONING AMPLIFIER )