HVACopediaGoodman · Furnace
b1 Lost communication with blower motor
What the control is telling you
The control cannot talk to the blower motor. Furnace will not run. ComfortNet thermostat shows MOTOR COMM b1.
Applies to: GMVC95/AMVC95 upflow and *CVC9 counterflow two-stage furnaces
Likely causes
- Loose motor control (signal) leads
- Failed blower motor
- Failed furnace control
Test and repair steps
- Safety turn power off before working on the control or wiring.
- Check and reseat the motor control harness at both ends.
- Check the motor. Replace if failed.
- If the motor and harness are good, replace the control.
Settings for these units
- Normal status displays (7-segment) · Goodman/Amana GM9S96/AM9S96
- Normal status displays (7-segment) · Goodman/Amana GM9S80/AM9S80
- Normal status displays (7-segment) · Goodman/Amana GM9C96/AM9C96
- Minimum recommended filter size · Goodman/Amana GM9C96/AM9C96
Models that show this code
10 models in Goodman/Amana *MVC95/*CVC9 two-stage ComfortNet
Other codes on the same units
- 88 Power-up self check
- b0 Blower motor not running
- b2 Blower motor size does not match model data
- b3 Blower motor limiting (power, temperature or speed)
- b4 Blower motor trip (lost rotor control or high current)
- b5 Blower motor locked rotor
- b6 Blower motor over/under voltage or over temperature
- b7 Blower motor missing parameters
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Source: Goodman *CVC9/95 & *MVC95 Installation Instructions IO-341D (08/2010), Troubleshooting Chart p.53-57. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.