Goodman Furnace EAF Code: Lost Communication With the R-32 Refrigerant Sensor (Meaning, Fixes)

What the code means

Goodman's R-32-ready furnaces (for example the GR9S96, GD9S96 and GR9S92 families) have a control board that can shut off the gas heat and run the blower if the leak sensor on the indoor evaporator coil detects R-32 refrigerant. Goodman's status table lists EAF as the A2L communication alarm, and the installation manual describes it as the furnace losing communication with the R-32 sensor while it is in mitigation mode, so the furnace stops heating and only the fan operates. The R-32 function is ON by default. If the furnace is paired with an R-410A outdoor unit, or is installed as a furnace only with no air conditioning, Goodman says the R-32 function must be turned off in the board's A2E (A2L Function Enabled) menu for the furnace to run properly. If the system really does use R-32, the sensor wire from the coil has to be plugged into the furnace control board, and EAF then points to a loose or damaged sensor wire or a failed sensor. Goodman's manual also mentions a green LED next to the sensor connection: after startup it blinks when the board is talking to the sensor and stays off when there's no signal. EAF is different from EAL, which means the sensor actually detected a refrigerant leak.

Likely causes

• The furnace is paired with an R-410A air conditioner or heat pump, or has no cooling at all, but the R-32 (A2L) function was left at its factory default of ON
• A new R-32 coil was installed but its sensor wire was never run to the furnace and plugged into the control board (it can be hidden behind the coil covers)
• A loose R-32 sensor wire connection at the board or the sensor
• A damaged R-32 sensor wire, for example pinched, cut or rubbed through on a sharp edge
• A failed R-32 sensor

Safe DIY checks

1. Check what the furnace is paired with. Look at the outdoor unit's rating plate or your install paperwork to see whether the system uses R-32 or R-410A, or whether you have no air conditioning at all.
2. If the system uses R-32, turn the furnace power off at its switch and check that the sensor wire coming from the indoor coil is plugged firmly into the furnace control board and isn't pinched or damaged.
3. After restoring power, look for the green LED next to the sensor connection on the board. Goodman says it blinks when the board and sensor are communicating and stays off when there's no signal.
4. Don't change the A2E setting yourself unless you're certain the system does not use R-32. Goodman and Daikin both say the R-32 function must not be disabled on a furnace paired with an R-32 outdoor unit, since it's a refrigerant-leak safety feature.
5. If the furnace was just installed, call the installer back. Setting the A2E menu correctly or connecting the coil sensor is part of the installation.

Related codes

• 3 flashes Goodman Gas Furnace 3 flashes
• 4 flashes Goodman Gas Furnace 4 flashes
• 6 flashes Goodman Gas Furnace 6 flashes
• 7P1 (IdL) Goodman Gas Furnace 7P1 (IdL)
• 13 Carrier Gas Furnace 13
• 14 Carrier Gas Furnace 14

All Goodman codes →

Sources

1. Goodman *R9S96/*D9S96 & *R9S92 installation instructions IOG-2037B (R-32 Information: R-32 function ON by default, A2E menu, sensor wire routing, green LED; troubleshooting chart EAF and EAL; maintenance R-32 sensor wire check)
2. Goodman GR9S96-U wiring diagram status and fault table (A2L communication alarm = E A F; A2L mode is enabled by default; non R-32 systems need default settings changed)
3. Daikin Technical Service Bulletin TSB C-GN-OT-0077, Troubleshooting EAF Error Code (June 5, 2025; check the R-32 setting before replacing the control board, A2E steps)