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Goodman · Furnace

EE8 High-stage pressure switch closed at start of heating cycle

Medium severity Goodman/Amana GM9C96/AM9C96

What the control is telling you

On a two-stage furnace the high-stage pressure switch circuit is already closed at the start of a heat call. The furnace runs on low stage only (inducer still operates). Flowcharts call this code E8.

Applies to: Goodman/Amana two-stage 96% furnaces GM9C96, GC9C96, AM9C96, AC9C96

Likely causes

  • High-stage pressure switch contacts stuck closed
  • Short in the pressure switch circuit wiring

Test and repair steps

  1. Power off, remove the wires from the high-stage pressure switch and ohm the contacts with the inducer off - they must be open.
  2. Replace the high-stage pressure switch if the contacts are closed with no vacuum.
  3. If the switch is good, find and repair the short in the switch wiring.
  4. Retest a high-fire call (W1+W2) and confirm the furnace stages up.

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Source: Goodman RS6612020r1 (GM9C96/GC9C96/AM9C96/AC9C96 service), 2 Stage Troubleshooting Codes, p.36; Error Code E1, E2 flowchart p.40. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.