Goodman GMVM970803BN Error Code b2: Blower HP Mis-Match
What Does Code b2 Mean?
A b2 code on the Goodman GMVM970803BN indicates a mismatch between the blower motor horsepower rating programmed in the control board's shared data set and the actual blower motor installed in the furnace. This furnace uses a removable memory card that stores model-specific configuration data including the expected blower motor horsepower. When the motor reports a different horsepower than the configuration expects, the furnace refuses to operate — running an incorrectly matched motor could result in improper airflow, overheating, or motor damage.
This code most commonly appears after a service call where a replacement blower motor was installed with a different HP rating than the original, or when the wrong memory card was used to configure the control board. It can also occur if a control board was replaced with one configured for a different model in the *MVM97 family. Because different BTU ratings within this model family use different blower sizes, mixing components from different models creates this HP mismatch condition.
A qualified HVAC technician must verify that the installed blower motor matches the specifications on the furnace rating plate, and that the memory card installed in the control board contains the correct shared data set for this specific model number. If the motor HP is wrong, it needs to be replaced with the correct HP motor. If the memory card data is wrong, the technician must insert the correct memory card with power off, cycle power to load the data, and then remove the card.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Call a technician to verify that the installed blower motor HP matches the furnace rating plate specifications and that the correct memory card data set is loaded for this specific model number
- If either the motor or memory card data is incorrect following a prior repair, the technician must source and install the correct components — mismatched HP can damage the heat exchanger
✓ Verified against manufacturer service manual — March 2026