Goodman GMVM970803BN Error Code E9: High Stage Pressure Switch Stuck Open
What Does Code E9 Mean?
An E9 code on the Goodman GMVM970803BN means the high stage pressure switch did not close when the inducer motor was energized, preventing the furnace from operating at its full heating capacity. While the low stage pressure switch may be functioning correctly — allowing low-fire operation — the high stage switch cannot confirm sufficient venting airflow for the higher firing rate. As a result, the inducer motor continues running and the furnace operates on low stage only.
The causes of E9 mirror those of E2 (low stage pressure switch open) but apply specifically to the high stage switch, which requires greater negative pressure to close. Common culprits include a partially blocked flue pipe that allows enough airflow for low stage but not high stage, a deteriorating pressure switch hose that leaks just enough to prevent the switch from sensing the required pressure, or condensate drain blockage that increases backpressure in the system. The H-fitting atmospheric port being blocked is another possible cause. An inducer motor that cannot achieve sufficient speed for high-stage venting will also trigger this code.
A technician should inspect the pressure switch hose for cracks or moisture, verify the flue and intake pipes are clear and properly sized, check the condensate drain, and measure the actual negative pressure at the switch tap. The replacement pressure switch and induced draft blower must match the specifications for this model.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Schedule service — a technician needs to inspect the venting system, pressure switch hose, and condensate drain for blockages preventing sufficient high-stage draft
- The technician should measure negative pressure at the high stage switch tap to determine whether the issue is insufficient inducer performance or a faulty switch, and replace components with correct model-specific parts
✓ Verified against manufacturer service manual — March 2026