Goodman GMVC960803BN Error Code EC3: Bluetooth Module Network Communication Alarm
What Does Code EC3 Mean?
The Goodman GMVC960803BN can be fitted with an optional Bluetooth module that connects to the ComfortNet network so the system can be paired with a phone app over Bluetooth. Code EC3 simply reports that the furnace's Integrated Control Module can no longer communicate with that Bluetooth module.
To be plain about it: EC3 has no effect on heating whatsoever. The furnace continues to fire, stage, and circulate air exactly as normal — the only thing you lose is the ability to connect to the furnace wirelessly from a phone app. If you don't use the Bluetooth/app feature, EC3 has essentially no practical impact on you at all.
This makes EC3 the most benign of the five EC communication alarms on this furnace. It is far less consequential than EC1 (the main thermostat data link) or EC2 (the E-Module expansion control), and it does not involve any equipment or accessory relay like EC4 and EC5 do. It is purely about the phone-connectivity accessory.
Common causes are a Bluetooth module that has come loose or lost power, a damaged data connection between the module and the furnace board, or a failed module. Once the module is reconnected and talking again, the control board clears EC3 automatically.
What You'll Notice
- You can no longer pair with or connect to the furnace from its phone app over Bluetooth
- EC3 shows on the furnace's 7-segment LED display, but heating runs completely normally
- The app reports the furnace as offline or not found
- No change at all in comfort — the thermostat still controls heat as usual
- The code clears by itself once the Bluetooth module is reconnected and communicating
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Bluetooth module disconnected or failed | Most common | ✗ Call a pro → |
| Wiring issue between control and Bluetooth module | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms that a Bluetooth module is installed, then checks that it has power and that its data connection to the furnace control board is secure and undamaged. They verify the module is recognized on the ComfortNet network. Because heating is unaffected, this is purely a connectivity check — if power and wiring are good but EC3 remains, the Bluetooth module itself is typically at fault.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- You rely on the phone-app connection and EC3 persists after the module's connections have been checked
- The Bluetooth module is confirmed installed but is not recognized on the network
- The data or power connection to the Bluetooth module shows visible damage or looseness
- App pairing does not return even though the furnace is otherwise heating normally
Frequently Asked Questions
Is my heat affected by EC3?
No, not at all. EC3 only concerns the optional Bluetooth module used for phone-app connectivity. The furnace keeps heating normally regardless of this code.
Do I need to fix EC3 right away?
Only if you actually use the Bluetooth/app feature. If you don't, EC3 has no practical effect and there is no urgency. If you do want app control back, a technician can check or replace the module.
Is EC3 the least serious of these communication codes?
Yes. Of the Goodman EC alarms, EC3 is the most benign because it only touches phone connectivity — unlike EC1, which affects the main thermostat link, or EC4/EC5, which involve external relay modules.
✓ Verified against manufacturer service manual — March 2026