Goodman GMVM970803BN Error Code E1: Low Stage Pressure Switch Stuck Closed
What Does Code E1 Mean?
An E1 code on the Goodman GMVM970803BN indicates the low stage pressure switch is stuck in the closed position before the heating cycle has even begun. This switch is a safety device that monitors airflow through the heat exchanger and venting system. The control board performs a pre-cycle check to confirm the switch is open (its default unpressurized state) before proceeding with ignition. If the switch is already closed at startup, the furnace cannot verify that proper venting conditions exist, so it refuses to operate.
This condition most commonly occurs when the pressure switch contacts have become mechanically stuck or welded together, or when there is an electrical short in the wiring between the pressure switch and the control board that makes the switch appear closed even when it is not. In both cases, the furnace cannot trust the pressure switch circuit and will refuse to start the heating sequence.
The ComfortNet thermostat will display a "Call for Service" icon and scroll "Check Furnace" when this code is active. This is not a DIY-serviceable condition — the diagnostic requires a multimeter to check switch contacts and wiring continuity, and correction requires replacing the pressure switch or repairing the wiring harness.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Low stage pressure switch contacts sticking | Most common | ✗ Call a pro → |
| Short in pressure switch circuit wiring | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Call a technician to test the low stage pressure switch with a multimeter — if contacts are stuck closed, the switch must be replaced with the correct model-specific part
- A technician should also inspect the wiring harness between the pressure switch and control board for shorts or damage that could produce a false closed-switch reading
✓ Verified against manufacturer service manual — March 2026