Goodman GMVC960803BN Error Code EE8: High Stage Pressure Switch Stuck Closed
What Does Code EE8 Mean?
Error code EE8 on the Goodman GMVC960803BN means the integrated control module checked the high-stage pressure switch at the start of a heating cycle and found its circuit already closed, before the induced draft blower had ramped up to high-stage speed. On this furnace that switch should be OPEN until the inducer is actually running fast enough to create high-stage draft, so an early closure is treated as a fault.
The key thing to understand about EE8 is that it is not a no-heat code. Because this is a two-stage, variable-speed 96% AFUE furnace with separate low- and high-stage pressure switches, the low-stage circuit is unaffected and the furnace simply continues to run on low stage. You will have partial, reduced heat rather than a dead furnace — which is why this code carries a low severity. The trade-off is that on very cold days the furnace can never step up to full output, so run times get long and the home may not reach the set temperature.
EE8 is the high-stage counterpart of EE1 (the same stuck-closed fault on the low-stage switch) and the mirror image of EE9, where the high-stage switch is faulted for the opposite reason — failing to close. The most common cause of EE8 is high-stage switch contacts that have stuck or fused closed. A short in the high-stage pressure switch wiring can create a continuous circuit that mimics a closed switch and produces the same code.
What You'll Notice
- The furnace runs and produces heat, but never reaches full output on cold days
- Heat feels weak and run times are long because the furnace is stuck on low stage
- The 7-segment diagnostic display reads EE8
- The home struggles to reach the thermostat setpoint during very cold weather
- Low-stage operation otherwise looks and sounds normal
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| High stage pressure switch contacts sticking closed | Most common | ✗ Call a pro → |
| Short in high stage pressure switch wiring | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician reads the EE8 code and uses a multimeter to check the high-stage pressure switch while the inducer is off or running at low speed. The switch should read open under those conditions; if it shows continuity (closed) when there is no high-stage draft, the switch is faulty and is replaced.
If the switch tests open when isolated, the technician inspects the high-stage switch wiring and connector for a short between conductors, a pinched wire, or moisture bridging the terminals. Because low-stage heat continues to work, this diagnosis can usually be done without leaving the home without any heat.
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:
- The furnace only runs on low stage and will not step up to full heat, with EE8 displayed
- The high-stage pressure switch reads closed on a meter when it should be open
- EE8 remains after the high-stage switch has been replaced, pointing to a wiring short
- The home cannot reach setpoint on cold days because high-stage heat is unavailable
Frequently Asked Questions
Is it safe to keep using the furnace with an EE8 code?
The furnace will keep running on low stage and is not in a lockout, so you will still get some heat. However, because it cannot reach full capacity, it is worth having it diagnosed before the coldest weather. Have a qualified HVAC technician confirm nothing else is wrong before relying on it long term.
Why do I still have heat if there is an error code?
This furnace has separate pressure switches for its low and high firing rates. EE8 only affects the high-stage switch, so the low-stage side keeps operating normally and delivers reduced heat. That is why EE8 is a partial-heat fault rather than a complete no-heat shutdown.
How is EE8 different from EE9?
Both involve the high-stage pressure switch, but they are opposite faults. EE8 means the switch is stuck closed before the cycle starts, usually from bad contacts or a wiring short. EE9 means the switch fails to close when it should, usually from a venting or hose problem. In both cases the furnace falls back to low stage.
✓ Verified against manufacturer service manual — March 2026