Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Headup Display Communication Stop Mode

DESCRIPTION

Detection Item

Symptom

Trouble Area

Headup Display Communication Stop Mode

Any of the following conditions are met:

Communication stop for "Head Up Display" is indicated on the "Communication Bus Check" screen of the Techstream.
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Communication stop history for "Head Up Display" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "Head Up Display" is 6 or more.)
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Communication system DTCs (DTCs that start with U) that correspond to "Headup Display Communication Stop Mode" in "DTC Combination Table" are output.
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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.
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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.
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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.
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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 (METER MIRROR SUB-ASSEMBLY BRANCH LINE)

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

(b) Disconnect the H1 meter mirror sub-assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
H1-12 (MPX1) - H1-13 (MPX2)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

*a	Front view of wire harness connector (to Meter Mirror Sub-assembly)

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (METER MIRROR SUB-ASSEMBLY)

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
H1-4 (ES) - Body ground	Cable disconnected from negative (-) battery terminal	Below 1 Ω

*a	Front view of wire harness connector (to Meter Mirror Sub-assembly)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
H1-2 (B) - Body ground	Always	11 to 14 V
H1-1 (IG) - Body ground	Engine switch on (IG)	11 to 14 V

REPLACE METER MIRROR SUB-ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Smart Key System(for Entry Function, Gasoline Model): Front Passenger Side Door Entry Lock and Unlock Functions do not Operate
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Toyota Avalon (XX50) 2019-2022 Owners Manual