Goodman GMVM970803BN Error Code E8: High Stage Pressure Switch Stuck Closed

What Does Code E8 Mean?

An E8 code on the Goodman GMVM970803BN indicates the high stage pressure switch is stuck in the closed position before the heating cycle begins. This modulating furnace has both a low stage and a high stage pressure switch, each monitoring venting at their respective firing rates. The control board verifies both switches are open (their default state) at the start of each heating cycle. If it finds the high stage switch already closed, it flags the E8 fault.

Unlike a complete pressure switch failure, this code allows the furnace to continue operating in low stage (reduced output) mode only. You may still receive some heat, but the furnace cannot fire at its full rated capacity. During very cold weather or when the home requires rapid warm-up, this reduced output may be insufficient to maintain comfort.

The cause is the same as E1 for the high stage switch: mechanically stuck contacts within the switch body, or a short circuit in the wiring between the switch and the control board. A qualified HVAC technician should test the high stage pressure switch with a multimeter to confirm whether the contacts are physically stuck, inspect the wiring for shorts, and replace the switch if defective. The replacement must match the original set point specifications for this model, as an incorrect switch can create safety hazards.

Common Causes

When to Call a Professional

Contact a licensed HVAC technician if:

• Schedule service — a technician should test the high stage pressure switch with a multimeter and replace it with the correct model-specific part if contacts are stuck closed
• The technician should also inspect wiring between the pressure switch and control board for shorts that could cause the circuit to appear closed regardless of switch state

✓ Verified against manufacturer service manual — March 2026