Goodman furnace d2: Dehumidification, high stage cooling, communicating mode
d2 means the system is removing humidity while cooling on the compressor's high stage. Normal operation, and the mode used when both heat and humidity need dealing with at once.
Applies to: Goodman GMVM97, GCVM97 and Amana AMVM97 modulating gas furnaces with a two-character display, on a communicating system with a two stage compressor.
What it means
This is dehumidification with full cooling capacity. The control uses it when the cooling load is high enough that low stage cannot keep up, but humidity still needs managing — a hot, humid afternoon rather than a mild damp one. Blower speed is still reduced relative to straight cooling, so the air coming from the registers is colder and there is less of it. Someone who checks the display on the hottest day of the year and sees an unfamiliar two character code is looking at the system working at full capacity, not failing.
Most common causes
- A communicating thermostat calling for cooling and dehumidification with the compressor on high stage.
- A high cooling load combined with high humidity.
- The system stepping up from d1 because low stage could not satisfy the call.
How to diagnose it
- Note the outdoor conditions. High stage on a hot humid day is correct behaviour.
- Air that is colder but lower in volume than usual is the expected result of this mode.
- If the system sits in d2 for long periods in mild weather, that is worth investigating — it suggests the equipment is not keeping up, or the humidity setpoint is unrealistic.
- Compare against d1, the low stage version of the same mode.
How to fix it
- Nothing. This is normal operation at full capacity.
- If the system cannot satisfy the thermostat while in this mode, the complaint is capacity or charge, not this code.
- Check the humidity setpoint before assuming a fault.
Notes
Reading d1 and d2 over a season is a genuinely useful diagnostic. A system that never reaches d2 is comfortably sized; one that lives in it is not.
Related
- d1 — Dehumidification, low stage cooling, communicating mode
- C2 — High stage compressor, cooling mode
All codes for this manufacturer
Goodman and Amana furnace fault codes — every code, with what differs between models.
Models this code appears on
From the manufacturer's per-model database. If your model is not listed, this code may not exist on your board, or it may mean something different — check the model page.
What the fix costs
Nothing, when d2 shows on a hot humid afternoon — that is full-capacity operation, not a fault. The scenario with a bill attached is the one flagged above: a system living in d2 through mild weather. Investigating that starts at a $75–150 diagnostic visit (repair cost guide; usually credited against repairs), and the likely findings are on the cooling side — dirty coil, low charge, undersized equipment — rather than in the furnace, whose blower is demonstrably answering the call whenever d2 is displayed. That point is worth carrying into the conversation: d2 on the display is evidence the indoor half is doing its part, which narrows where the money needs to go.
DIY or call a pro?
Two checks are free and safe: the thermostat's humidity target (an aggressive setpoint manufactures endless d2 hours) and the return filter, since a starved blower forces longer high-stage runs. Beyond that this is professional territory — the plausible culprits are refrigerant charge and coil condition, both of which require gauges and neither of which lives in the furnace cabinet. There is no reset worth trying; d2 is not a lockout, and clearing the display would only hide the information it is giving you.
What this looks like
From the outside, this usually shows up as there is no heat but nothing looks obviously wrong — that walkthrough covers what to check in order, and when it stops being a homeowner job.