Toyota 4Runner: Lost Communication with A/C ECU (U0164)

Toyota 4Runner Service Manual / Power Source / Network / Networking / Can Communication System / Lost Communication with A/C ECU (U0164)

DESCRIPTION

DTC Code	DTC Detection Condition	Trouble Area
U0164	There is no communication from the air conditioning amplifier assembly.	Power source or inside air conditioning amplifier assembly Air conditioning amplifier assembly branch wire or connector Air conditioning amplifier assembly

HINT:

For vehicles with a smart key system only.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:

Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE

1.	DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and branch wire.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ).

2.	CHECK FOR OPEN IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER ASSEMBLY BRANCH WIRE)

(a) Disconnect the F42 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
F42-11 (CANH) - F42-12 (CANL)	Ignition switch off	54 to 64 Ω

Text in Illustration

*a	Rear view of wire harness connector (to Air Conditioning Amplifier Assembly)

REPAIR OR REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY BRANCH WIRE OR CONNECTOR (CANH, CANL)

3.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - BATTERY AND BODY GROUND)

(a) Connect the cable to the negative (-) battery terminal.

NOTICE:

When disconnecting the cable, some systems need to be initialized after the cable is reconnected (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F42-14 (GND) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F42-21 (B) - Body ground	Always	11 to 14 V
F42-1 (IG+) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Rear view of wire harness connector (to Air Conditioning Amplifier Assembly)

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

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