Goodman Furnace Flash Codes Guide

The Goodman Furnace Flash Codes guide explains how to read and respond to the LED error flashes on Goodman and Amana furnaces, helping homeowners and technicians diagnose common issues quickly. This article covers code meanings, likely causes, troubleshooting steps, safety tips, and when to call a professional.

Flash Code	Meaning	Common Causes
1 Flash	Normal Operation / System On	Power and control board functioning
2 Flashes	Pressure Switch Continuity And Circuit Open	Blocked vent, faulty pressure switch, inducer motor issue
3 Flashes	Pressure Switch Not Closing	Vacuum hose leak, clogged vent, bad inducer
4 Flashes	Limit Circuit Is Open	Overheating, blocked return, faulty limit switch
5 Flashes	Open High Limit	Overheat condition, dirty flame sensor, fan problems
6 Flashes	Flame Rollout Switch or Limit Open	Flame rollout, venting issue, cracked heat exchanger
7 Flashes	Flame Sense Fault	Dirty flame sensor, faulty ignitor, bad flame rod wiring
8 Flashes	Ignition Lockout	Repeated failed ignition attempts, gas supply problem
9 Flashes	Blower Fault Or Continuous Fan Relay	Blower motor failure, relay malfunction
10 Flashes	Control Board Failure	Failed PCB, component short

How Goodman Furnace Flash Codes Work

Goodman furnaces use an LED on the control board to indicate system status by flashing a specific number of times. Each flash pattern corresponds to a diagnostic code that points to a subsystem or safety device. Understanding flash codes speeds troubleshooting and reduces trial-and-error repairs.

Where To Find The Flash Code LED

The LED is typically located on the furnace control board behind the front access panel. For many Goodman models the access panel must be removed and the door safety switch engaged to power the control board. The owner’s manual or control board diagram often labels the LED and lists codes.

Reading Flash Codes Correctly

Observe the LED for a full cycle: brief flashes separated by a short pause. Count the number of flashes in one sequence to identify the code. Some boards use two-digit codes (e.g., long flash then short flashes); consult the specific model documentation when patterns are not obvious.

Common Flash Codes And Detailed Troubleshooting

2 Flashes — Pressure Switch Continuity And Circuit Open

This code signals the control didn’t see the expected pressure switch closure. Check venting restrictions, condensate blockage (for high-efficiency units), and the inducer motor operation. Inspect the vacuum tubing and connections for cracks or disconnections.

3 Flashes — Pressure Switch Not Closing

The furnace failed to establish proper draft. Clean intake and exhaust vents of debris, birds’ nests, and snow. Verify the inducer motor runs and builds vacuum. Test the pressure switch with a multimeter; replace if it fails continuity when the inducer runs.

4–6 Flashes — Limit/High Limit/Flame Rollout

These codes indicate overheating or combustion air flow problems. Check air filters and return vents; restricted airflow causes heat buildup. Inspect the heat exchanger area for signs of flame rollout or soot. If flame rollout or a cracked heat exchanger is suspected, stop operation and call a licensed technician due to carbon monoxide risks.

7 Flashes — Flame Sense Fault

The control did not detect flame during ignition or early flame proved. Clean the flame sensor rod with fine abrasive pad and re-seat. Inspect wiring and grounding. If the ignitor glows but no flame is sensed, the sensor or its harness may need replacement.

8 Flashes — Ignition Lockout

After repeated failed ignition attempts the board locks out to prevent gas buildup. Verify proper gas pressure and valve operation. Confirm the ignitor integrity and flame rollout conditions. Resetting the thermostat or power momentarily may clear lockout, but repeat occurrences require professional inspection.

9 Flashes — Blower Or Relay Fault

This code suggests the blower motor or its relay did not operate as expected. Test blower capacitor, motor windings, and relay contacts. Check for seized bearings and electrical supply issues. Replacing a faulty blower motor or capacitor is common.

10 Flashes — Control Board Failure

A persistent 10-flash pattern often points to a defective control board or onboard component failure. Verify voltage to the board and secondary components. Replace the control board only after confirming peripheral parts are functional to avoid recurring failures.

Step-By-Step Troubleshooting Checklist

1. Record The Exact Flash Pattern And Any Accompanying Behavior.
2. Turn Power Off And Inspect Visible Components For Damage Or Loose Wires.
3. Check Air Filter, Vents, And Return Air For Blockages.
4. Confirm Inducer Motor And Blower Operation When System Calls For Heat.
5. Inspect Pressure Switch Tubing And Venting For Leaks Or Obstructions.
6. Test Flame Sensor And Ignitor Resistance Values Against Manufacturer Specs.
7. Verify Gas Supply And Proper Valve Operation.
8. If Safety Devices Indicate Combustion Issues, Discontinue Use And Call A Professional.

Safety Precautions When Diagnosing Flash Codes

Working on gas furnaces carries risks including electric shock, fire, and carbon monoxide. Always shut power at the switch or breaker before opening panels. If evidence of combustion leaks, flame rollout, or suspected heat exchanger cracks appears, stop using the furnace and contact a licensed HVAC technician immediately.

When To Call A Professional

Call a certified HVAC technician when codes indicate combustion safety, control board faults, heat exchanger issues, persistent ignition failures, or when electrical component testing is required. Licensed technicians have gas leak detection tools, combustion analyzers, and the training to address safety-critical repairs.

Replacing Common Parts Safely

Many homeowners can replace simple parts like filters or clean flame sensors, but replacement of gas valves, ignitors, blower motors, pressure switches, and control boards typically requires a licensed technician. Proper replacement ensures correct calibration, safe operation, and warranty compliance.

Preventative Maintenance To Avoid Flash Codes

• Change Air Filters Every 1–3 Months To Maintain Proper Airflow.
• Keep Intake And Exhaust Vents Clear Of Debris And Snow.
• Schedule Annual Professional Tune-Ups Including Combustion Analysis.
• Inspect And Clean The Flame Sensor During Routine Maintenance.
• Ensure Proper Thermostat Function And Wiring Connections.

Model Variations And Documentation

Goodman and Amana model lines may use slightly different flash code conventions. Always consult the furnace’s model-specific manual or the control board label for the definitive code list. Manufacturer websites provide manuals and parts diagrams for reference.

Understanding Two-Digit And Alternate Patterns

Some newer boards display two-digit codes using a long flash followed by a sequence of short flashes. In such cases the long flash represents the tens place and short flashes the units place. Cross-reference the control board part number and manual for accurate decoding.

Common Misdiagnoses To Avoid

Do not assume an electrical part failure without verifying gas and airflow conditions. Replacing a control board before checking sensors, switches, and venting often results in unnecessary expense. Use the LED code as a starting point and follow systematic diagnostics.

Resources And Further Reading

Manufacturer technical bulletins, model-specific manuals, and HVAC professional forums provide detailed wiring diagrams and diagnostic flows. For safety-critical concerns rely on accredited HVAC service providers and official Goodman documentation rather than unverified online advice.

Quick Reference: Action Matrix For Common Codes

Code	Immediate Action	Likely Professional Repair
2–3	Inspect venting, vacuum hose, inducer	Replace pressure switch, inducer motor repair
4–6	Check filters, airflow, visual flame rollout	Repair venting, replace limit/rollout switch, heat exchanger assessment
7–8	Clean flame sensor, verify ignitor	Replace sensor/ignitor, adjust gas valve
9–10	Test blower and board power	Replace blower motor, capacitor, or control board

For installations in the United States, comply with local codes and standards when performing repairs or hiring contractors. The Goodman Furnace Flash Codes guide empowers informed decisions; however, do not substitute professional diagnostics for safety-critical furnace faults.