FieldBench
Goodman codes

Goodman

b4

Lockout

Trip / lost rotor

Motor tripped or lost rotor position while running.

Walk b4 in Diagnose

Sign in for the next measurement

First check

1 Is the wheel free?

Spin the Goodman GMVC96 blower by hand. Ice, debris, or a seized bearing is not a control problem. Confirm the motor type on this plate — serial ECM, 9-speed tap, or X-13 — before you grab a capacitor. Wheel interference, wet winding, failing module.

Expect: Wheel free. Correct motor family for this IFC.

The rest of the walkthrough is Diagnose.

On the plates

  • Wheel interference, wet winding, failing module.
  • Line voltage sag at the motor during ramp.
  • Replace motor only after harness and static are clean.

Plates that use b4