Keyless Access System Check

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2025 Honda Odyssey, 2024 Honda Odyssey, 2023 Honda Odyssey, 2022 Honda Odyssey, and 2021 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.

1. Connect the HDS to the data link connector (DLC)

2. Turn the vehicle to the ON mode.

3. On the HDS screen, at SYSTEM SELECTION MENU, enter ONE-PUSH START, then select KEYLESS ACCESS CONTROL UNIT or BACKUP CONTROL UNIT.

NOTE: If the HDS does not communicate, check the body control module power, ground, K line, and L-line connectors.

4. At KEYLESS ACCESS CONTROL UNIT, enter KEYLESS ACCESS SYSTEM INFORMATION, then select SYSTEM CHECK 1 or SYSTEM CHECK 2.

5. At BACKUP CONTROL UNIT, enter SYSTEM INFORMATION, then select SYSTEM CHECK. If the HDS displays NORMAL N-1, the immobilizer system is OK at this time, refer to the STATUS LOG. If the HDS displays any other messages, check as follows:

System Check 1 (Keyless Access Control Unit)

System Check No.	Possible cause	Check items
A-1A-2A-3G-4	Keyless remote is mismatched No communication between body control module and keyless remote Keyless remote is not registered	Register the keyless remote LF antenna test Check antenna level with the HDS
B-1B-2G-1	PCM is not registered No communication between body control module and PCM Body control module is replaced	Register the PCM Check PCM Check for an open in the S-NET lines Register the body control module
C-1C-2G-2G-3	Body control module is not registered Body control module is replaced	Register the body control module Check body control module Check for an open in the S-NET lines
C-3C-4G-5	Body control module is replaced Communication error between body control module and electric steering lock * Electric steering lock is not registered *	Register the body control module Check for an open or short in the IGN TRX line Check electric steering lock * Register the electric steering lock *

*: With electric steering lock

System Check 2 (Keyless Access Control Unit)

System Check No.	Possible cause	Check items
D-1D-2D-3	S-NET line is open or short No communication between body control module and PCM	Check for an open or short in the S-NET lines Check body control module Check PCM
D-4D-5	IGN TRX line is open or short	Check for an open or short in the IGN TRX line

System Check (Backup Control Unit)

System Check No.	Possible cause	Check items
A-1A-2A-3	Keyless remote is mismatched Keyless remote is not registered Engine start/stop switch failure	Register the keyless remote Check engine start/stop switch

System Check No.	Possible cause	Check items
B-1B-2	PCM is replaced Communication error between body control module and PCM	Register the PCM Check PCM
C-1C-2	Body control module is replaced	Register the body control module Check body control module Check for an open in the S-NET lines
D-1D-2D-3	S-NET line is open or short No communication between body control module and PCM	Check for an open or short in the S-NET lines Check body control module Check PCM
E-1E-2E-3E-4E-5	Body control module is not registered PCM is not registered Keyless remote is not registered	Register the body control module Register the PCM Register the keyless remote
F-1F-2F-3F-4F-5F-6	Special mode	Turn the vehicle to the ON mode and then select the OFF (LOCK) mode with a registered keyless remote