GOODMAN DIAGNOSTIC REFERENCE DUAL 7-SEGMENT DISPLAY (TWO-STAGE VARIABLE-SPEED) DOC GOODMAN-B4

Goodman furnace: Motor Trips (b4)

Motor Trips (b4). The ECM motor sensed a loss of control or became overloaded and shut down.

b4 YOUR LIGHT: DISPLAY CODE B4 — MATCH IT ABOVE

Professional repair

What does b4 mean on a Goodman furnace? The ECM motor sensed a loss of control or became overloaded and shut down.

Motor and load diagnosis. DIY part cost: $400–800 — a pro visit for this class of fault typically runs $150–350.

What causes it (in order of likelihood)

ECM Blower Motor

$400–800 · Model-specific

Always match parts against your model's parts list — part numbers vary within a series.

GMVC96 · GCVC96 · AMVC96 · ACVC96

Different Goodman generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.

Verified against Goodman GMVC96/GCVC96 Service Manual, p.45

Last verified 2026-07-06 · how we verify