LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Acura >> 2021 >> RDX Base >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Security System / Keyless Entry System - Testing & Troubleshooting >> Repair Procedures, Tests >> Keyless Access System Check
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Keyless Access System Check

1. Connect the HDS to the data link connector (DLC) - Refer to: How to Troubleshoot the Body Electrical (2019 2020 2021) or How to Troubleshoot the Body Electrical (2022 2023) .

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.

6. 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-1
A-2
A-3
G-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-1
B-2
G-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-1
C-2
G-2
G-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-3
C-4
G-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-1
D-2
D-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-4
D-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-1
A-2
A-3
  • Keyless remote is mismatched
  • Engine start/stop switch failure
  • Keyless remote is not registered
  • Register the keyless remote
  • Check engine start/stop switch
B-1
B-2
  • PCM is replaced
  • Communication error between body control module and PCM
  • Register the PCM
  • Check PCM
C-1
C-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-1
D-2
D-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-1
E-2
E-3
E-4
E-5
  • Body control module is not registered
  • PCM is not registered
  • Keyless remote is not registered
  • Register the body control module
  • Register the keyless remote
  • Register the PCM
F-1
F-2
F-3
F-4
F-5
F-6
Special Mode Turn the vehicle to the ON mode and then select the OFF (LOCK) mode with a registered keyless remote