Goodman Furnace b4 Error Code — Meaning & Repair Cost (2026)
Blower motor current trip or lost rotor control. Below: the most likely causes, and what the matching repair costs — Estimated national ranges with a metro localizer. Reviewed July 2026.
What b4 means
Blower motor current trip or lost rotor control.
Likely causes, most common first
- Abnormal motor loading or a sudden change in speed or torque
- Sudden blockage of the furnace air inlet or outlet
- Blocked filters or very restrictive ductwork
Also applies to Amana — these brands share the same control platform, so the code and its causes read the same.
Base: 1 published national repair-cost guide (retrieved 2026-07) · full source registry on the methodology page · Code meaning & causes · Reviewed July 2026
What it usually costs to fix Estimated
b4 on a Goodman furnace resolves to the gas furnace blower motor replacement problem. Goodman parts typically run ×0.85 against the mainstream baseline (Repeatedly cited as the cheapest-parts brand with the widest generic/aftermarket distribution ("Goodman parts are everywhere and inexpensive"); it is the $25-wholesale-capacitor reference point cost guides use when pricing Trane and other brands at a 20-40% premium above it.), and the ranges below already include it.
$330–$1,395 national estimate to fix the fault behind b4 (Goodman parts ×0.85). Enter a ZIP to localize.
| Most common repair | Typical total | DIY? |
|---|---|---|
| PSC blower motor replacement (single-speed) | $330–$750 | Pro recommended |
| ECM / variable-speed blower motor replacement (+ module) | $565–$1,395 | Pro recommended |
Plus a typical service-call / diagnostic fee of $75–$150, often credited toward the repair.
Pick a quality tier for a class-typical estimate, or a specific brand to override it (brand adjusts the parts portion only). Enter a ZIP or Canadian postal code to localize to your metro's labor costs. Everything updates without a page reload; no data leaves your browser except the shard lookup.
Base: 2 published national repair-cost guides (retrieved 2026-07) · full source registry on the methodology page · National base range (BLS OEWS May 2025 + BEA RPP 2024) · Reviewed July 2026 · Estimated
Codes are universal — your location changes the repair price, never the code's meaning. See the methodology for the exact localization formula and sources.
Reviewed by a Red Seal–certified appliance technician who also holds a Technical Safety BC gas ticket (Gas-C) and an ODS/halocarbon refrigerant ticket (CFC/HCFC/HFC).