Bryant 355MAV Error Code 42: Inducer Motor Fault
What Does Code 42 Mean?
Status code 42 on the Bryant 355MAV indicates an inducer motor fault. The inducer (also called the draft motor) either has not started within 20 seconds after a call for heat, its RPM is outside the valid range of operation, or the RPM signal was lost for 5 seconds during operation.
The inducer motor is the first component to activate in a heating cycle. It creates a draft through the heat exchanger to safely vent combustion gases outside. Without proper inducer operation, the furnace cannot proceed to ignition because the pressure switches will not close.
While a failed inducer motor is the most common cause, restricted vent pipes or combustion air supply can also cause the motor to operate outside its normal RPM range. Blockages force the motor to work harder or create uneven airflow, causing RPM fluctuations that trigger this fault. Checking for vent blockages is a reasonable DIY step before calling a technician for motor replacement.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Failed inducer motor | Most common | ✗ Call a pro → |
| Restricted vent or combustion air supply | Common | ✗ Call a pro → |
| Improper inducer motor wiring | Uncommon | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- The inducer motor does not start at all
- The inducer motor makes grinding, rattling, or screeching noises
- Vents are clear but code 42 persists
- The inducer motor runs but the furnace still does not ignite
- You notice a burning smell coming from the inducer motor area
✓ Verified against manufacturer service manual — March 2026