NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): Air Conditioning Amplifier Communication Stop Mode; 2019 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 01/2019]

Last Modified: 05-13-2024	6.11:8.1.0	Doc ID: RM100000001CBOB
Model Year Start: 2019	Model: GR Corolla	Prod Date Range: [06/2018 - 01/2019]
Title: NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): Air Conditioning Amplifier Communication Stop Mode; 2019 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 01/2019]

Air Conditioning Amplifier Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
Air Conditioning Amplifier Communication Stop Mode	Any of the following conditions are met: Communication stop for "Air Conditioning Amplifier" is indicated on the "Communication Bus Check" screen of the Techstream. Click here Communication stop history for "Air Conditioning Amplifier" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "Air Conditioning Amplifier" is 6 or more.) Click here Communication system DTCs (DTCs that start with U) that correspond to "Air Conditioning Amplifier Communication Stop Mode" in "DTC Combination Table" are output. Click here	Air conditioning amplifier assembly branch line or connector Power source circuit of air conditioning amplifier assembly Air conditioning amplifier assembly ground circuit Air conditioning amplifier assembly

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
Click here
Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
Click here
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
Click here
Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.	CHECK FOR OPEN IN CAN BUS LINES (AIR CONDITIONING AMPLIFIER ASSEMBLY BRANCH LINE)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the I49 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I49-2 (CANH) - I49-1 (CANL)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

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

NG

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY)

OK

2.	CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I49-17 (GND) - Body ground	Cable disconnected from negative (-) battery terminal	Below 1 Ω

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

(b) Reconnect the cable to the negative (-) battery terminal.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
I49-5 (B) - Body ground	Always	11 to 14 V
I49-6 (IG+) - Body ground	Engine switch on (IG)	11 to 14 V

OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)