Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
AcuraLink System Status Indicator Does Not Come On
NOTE:
- Check the vehicle 12 volt battery condition first - Refer to: 12 Volt Battery Test (Without SH-AWD) or 12 Volt Battery Test (With SH-AWD) .
- Check the connectors for poor connections or loose terminals.
- Self-diagnostic function check
- 1. Turn the vehicle to the ON mode.
- 2. Press and hold the HANG-UP/BACK button on the audio remote-HFL switch for more than 5 seconds.
Is the telematics prompt played?
YES: "The TCU is OK." is played
Go to step 2.
YES: "The following failure is detected..." is played
Check for telematics system DTCs .
NO
Go to navigation DTC 2721 (TCU Diag) troubleshooting - Refer to: Audio-Navigation System DTC Troubleshooting: 2721 (With Auto Idle Stop System), or Audio-Navigation System DTC Troubleshooting: 2721 (Without Auto Idle Stop System) .
- Problem verification
- 1. Press and hold the HANG-UP/BACK button on the audio remote-HFL switch for more than 5 seconds.
- 2. Check for AcuraLink indicator.
Is the AcuraLink indicator blinking green and red alternately?
YES
Intermittent failure, the system is OK at this time.
NO
The failure is duplicated, go to step 3.
- Determine possible failure area (TCU LED lines, others)
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the following connector.
Roof console module 24P connector - 3. Turn the vehicle to the ON mode.
- 4. Press and hold the HANG-UP/BACK button on the audio remote-HFL switch for more than 5 seconds.
- 5. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode Roof console module 24P connector: disconnected Test point 1 Roof console module 24P connector No. 16 Test point 2 Body ground Test point 1 Roof console module 24P connector No. 17 Test point 2 Body ground Is there alternating battery voltage?
YES
Replace the roof console module .
NO
Go to step 4.
- Open wire check (TCU LED-RED line, TCU LED-GRN line)
- 1. Press and hold the HANG-UP/BACK button on the audio remote-HFL switch for more than 5 seconds.
- 2. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode Roof console module 24P connector: disconnected Test point 1 Telematics control unit connector A (36P) No. 19 - Refer to: Telematics Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or Telematics Control Unit Connector for Inputs and Outputs (Without Auto Idle Stop System) (2015-17), or Telematics Control Unit Connector for Inputs and Outputs (2018-19) Test point 2 Body ground Test point 1 Telematics control unit connector A (36P) No. 1 - Refer to: Telematics Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or Telematics Control Unit Connector for Inputs and Outputs (Without Auto Idle Stop System) (2015-17), or Telematics Control Unit Connector for Inputs and Outputs (2018-19) Test point 2 Body ground Is there alternating battery voltage?
YES
Repair an open in the wire (s) between the telematics control unit and the roof console module.
NO
The TCU LED-RED and the TCU LED-GRN wires are not open. Go to step 5.
- Shorted wire check (TCU LED-RED line, TCU LED-GRN line)
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the following connector.
Telematics control unit connector A (36P) - 3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Roof console module 24P connector: disconnected Telematics control unit connector A (36P): disconnected Test point 1 Telematics control unit connector A (36P) No. 19 - Refer to: Telematics Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or Telematics Control Unit Connector for Inputs and Outputs (Without Auto Idle Stop System) (2015-17), or Telematics Control Unit Connector for Inputs and Outputs (2018-19) Test point 2 Body ground Test point 1 Telematics control unit connector A (36P) No. 1 - Refer to: Telematics Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or Telematics Control Unit Connector for Inputs and Outputs (Without Auto Idle Stop System) (2015-17), or Telematics Control Unit Connector for Inputs and Outputs (2018-19) Test point 2 Body ground Is there continuity?
YES
Repair a short to body ground in the wire (s) between the telematics control unit and the roof console module.
NO
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.