Run capacitor
Common no-start and weak-compressor failure point. Match the microfarad and voltage rating.
Goodman Furnace E3 Error — Draft Motor Fault
E3 on a Goodman digital-display furnace means the induced draft blower failed to prove — the IFC board energized the inducer motor, waited for the pressure switch to close, and it didn’t close within the allowed window.
This error appears on newer Goodman models with digital displays (GMSS96, GCSS96, GMH80 series with updated controls).
What E3 Is Checking
The startup sequence:
- IFC energizes inducer motor
- Inducer spins up, creates negative pressure in the heat exchanger
- Pressure switch port senses suction, switch closes
- IFC receives “draft proven” signal, proceeds to ignition
If step 3 or 4 fails, E3 is stored.
E3 Root Causes
| Cause | Check |
|---|---|
| Condensate drain blocked | Water backed up, blocking switch port |
| Pressure switch hose cracked/off | Trace all small rubber hoses |
| Pressure switch failed | Won’t close under suction |
| Inducer motor not spinning | Bad motor, capacitor, or IFC output |
| Blocked flue or intake | No draft pressure builds |
| Cold weather ice blockage | Frozen condensate or flue ice |
Diagnosis Steps
Step 1 — Listen at Startup
Turn the thermostat to heat. Within seconds, you should hear the inducer motor spin up (a rushing sound). If you hear nothing:
- Check that the furnace has power
- Check that the inducer motor terminals have 120V (use a multimeter, carefully, with power on)
- If 120V is present and motor doesn’t run: bad motor or run capacitor
Step 2 — Check the Condensate System
High-efficiency Goodman furnaces produce water. The drain pan, trap, and lines must all be clear. Disconnect the drain line at the trap. If water doesn’t flow freely, the trap or line is blocked. Clean with warm water or blow it out. Check the pressure switch port on the inducer housing — it should be clear and dry.
Step 3 — Test the Pressure Switch
With power off, remove one hose from the pressure switch. Apply gentle suction by mouth while measuring continuity across the switch terminals. The switch should close (continuity) under suction. If it doesn’t, replace the switch.
Common Goodman pressure switch part numbers:
- B1370135 (single-stage 80% models)
- B13701-35 (90% models — verify on board label)
Step 4 — Check Flue and Intake
Go outside. Look at both PVC pipes (90%+ efficiency) or metal flue. Debris, bird nests, or ice on the exhaust will immediately cause E3. Clear any obstruction.
Step 5 — Inducer Motor Testing
If the motor runs but E3 persists, the motor may not be generating enough suction. Use a manometer at the pressure switch port — should read -0.4 to -0.8” WC with motor running. Low readings indicate a worn motor or leaking housing.
Parts Reference
| Part | Typical Cost |
|---|---|
| Pressure switch (OEM) | $30–70 |
| Pressure switch hose | $5–10 |
| Inducer motor (Goodman OEM) | $150–350 |
| Condensate trap | $15–30 |
| IFC board | $100–280 |
Technician Tips
Goodman furnaces use a simple LED flash system on the control board. The diagnostic LED is usually visible through the blower compartment window. Count the flashes between pauses — that’s your error code. One flash = normal operation. Two flashes = pressure switch fault. Three flashes = limit switch. Four flashes = flame sensor. Goodman flame sensors are notorious for carbon buildup — cleaning with emery cloth every 2-3 years prevents most lockout calls. The control board on GMS8 and GMSS9 models is particularly sensitive to voltage fluctuations — if you see multiple different codes, check the transformer output (should be 24VAC ±10%).
Prevention: Install a whole-house surge protector on the furnace circuit to prevent board damage from power spikes.
Need Replacement Parts?
Before ordering, match the furnace part to the model number, electrical rating, and failure symptom. Check current prices on Amazon - prices and availability change frequently.
E3 vs. E1
- E1 — typically pressure switch stuck open before inducer proves (sequence issue)
- E3 — draft motor specifically failed to prove during trial
On some Goodman models, these codes can overlap depending on firmware. Always verify with the specific wiring diagram on the inside of the furnace door.
Quick Reset
After fixing the underlying cause, restore power. The furnace should attempt startup automatically. If E3 clears and returns within one cycle, you have an intermittent issue — suspect condensate backing up in the line during operation, or an inducer motor that’s failing under load.