How to Check the Telematics Control Unit Status

NOTE:

Check the vehicle battery condition first - Refer to: Battery Test (2014 2015), or Battery Test (2016) .
The self-diagnostic function starts after you press and hold the HANG-UP/BACK button on the audio remote-HFL switch for 5 seconds, and ends if the telematics control unit returns to its idle state.

1. Turn the vehicle to the ON mode.

2. Press and hold the HANG-UP/BACK button (A) for more than 5 seconds, and self-diagnostic function begins.

Courtesy of HONDA, U.S.A., INC.

3. When the telematics control unit enters the self-diagnostic function, the following will occur:

While in diagnosis, the AcuraLink system status indicator blinks green and red alternately.
If the telematics control unit does not respond, go to AcuraLink services do not work troubleshooting - Refer to: AcuraLink Symptom Troubleshooting - AcuraLink services do not work, or AcuraLink Symptom Troubleshooting - AcuraLink system status indicator does not come on, or AcuraLink Symptom Troubleshooting - AcuraLink system status indicator does not come on (2017 2018 2019 2020) .
If the telematics control unit is OK, and there are no telematics DTCs, the telematics control unit says, "The TCU is OK."
If there are any telematics system DTCs stored, the telematics control unit says, "The following failure is detected - (detected DTC's description)." Check for telematics system DTCs.