HMI - IO52.0
Interface Controller - Non Navigation Unit, No Carplay/Android Auto
HMI - IO52.5
Interface Controller - Non Navigation Unit, Yes Carplay/Android Auto
HMI - IO62.0
Interface Controller - Navigation Unit, No Carplay/Android Auto
HMI - IO62.5
Interface Controller - Navigation Unit, Yes Carplay/Android Auto
ACM
Audio Controller
Connections & their functions
HMI Connections
ACM Connections
Troubleshooting
Understanding DTC U0184
The diagnostic trouble code U0184 signifies a loss of communication with the Audio Control Module (ACM). Troubleshooting this code involves understanding the interplay between the ACM and the Human Machine Interface (HMI). Common symptoms include a black screen or no audio output from the system.
For HMI issues:
1. Black screen but you can hear the music still playing then bad HMI.
2. Black screen but when you put the vehicle into reverse the screen comes on and displays rear camera then bad HMI. *Only applies to vehicles with backup camera.
3. Listen to the fan on the HMI. If you don't hear it spin up then bad HMI.
4. The screen is on but the screen is having ghost touching then bad HMI but this isn't 100% a bad HMI. Ghost Touching can be caused by bad HMI, ACM, screen digitizer, and/or video cable.
For ACM issues:
Communication failure between the ACM and HMI can also trigger U0184 or similar issues. This makes it necessary to systematically check communication links when diagnosing ACM problems.
1. No sound coming from the radio, screen is one but no audio from speakers then bad ACM. Make sure to check if the antennas
2. Screen is on but can't tune to any radio stations for AM/FM/XM.
3. The screen is on but the screen is having ghost touching then bad ACM but this isn't 100% a bad ACM. Ghost Touching can be caused by bad HMI, ACM, screen digitizer, and/or video cable.
Advanced diagnostic tools such as the Media Oriented Systems Transport (MOST) bus tester can help pinpoint whether the ACM or HMI is the failing module. Conducting comprehensive communication pathway testing is often necessary for accurate diagnosis.
If a Cx has upgraded their HMI/IO6 module and have lost access or the shop app won't work anymore and they have a 2017+ vehicle. Their LTE service was lost when they upgraded, Cx needs to call OnStar and have their service transferred to new module or have their radio connect to a phone's hotspot to allow the shop app access to the internet to work.