Bryant 315AAV Error Code 15: Blower Motor Lockout
What Does Code 15 Mean?
Status code 15 on the Bryant 315AAV is the blower motor lockout. This furnace uses a variable-speed ECM blower that talks back to the Variable Speed Furnace Control and reports its own speed. If the motor cannot spin up to at least 250 RPM, or it fails to communicate within the control's time limits, the board locks the blower function out and stops the furnace so it does not run without air movement.
Code 15 is the lockout escalation of status code 41 (blower motor fault). Code 41 is what the control flashes while it is still counting failed blower cycles; after enough successive failures the condition hardens into the 15 lockout. Because the ECM blower is essential to both heating and cooling, this lockout takes the whole system offline, not just heat.
The most common cause is a failed or seized ECM blower motor, followed by loose or damaged wiring between the control and the motor that interrupts the speed feedback. Diagnosing an ECM motor and its communication link requires meters, the correct motor programming, and disassembly, so it is a technician's job — not a homeowner repair.
What You'll Notice
- The furnace attempts to start but shuts down because the blower does not come up to speed
- Little or no air comes from the vents even though the furnace tries to run
- The status LED flashes one short then five long flashes
- The system stays down for both heating and cooling until the lockout clears or is serviced
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Failed or seized blower motor | Most common | ✗ Call a pro → |
| Loose or damaged wiring between control board and blower motor | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms the blower actually fails to spin or reach speed, then separates a motor problem from a communication problem: they inspect the wiring harness and connectors between the control and the ECM motor for looseness or damage, verify the motor has proper power and programming, and check that the blower wheel is not seized or obstructed. A motor that will not turn or respond points to the ECM itself; intact hardware with lost feedback points to wiring.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The blower will not start or cannot come up to speed
- The furnace and air conditioner both fail because the shared blower is locked out
- The lockout returns after each 3-hour auto-reset
- You hear the motor try and stall, or you smell an overheated-motor odor
Frequently Asked Questions
How is code 15 different from code 41 on the Bryant 315AAV?
Code 41 is the blower motor fault the control reports as it accumulates failed cycles. Code 15 is the lockout that follows once those failures pile up, shutting the furnace down for about 3 hours.
Can I reset the blower lockout myself?
You can cycle power to clear the lockout, but if the motor or its wiring is the problem it will lock out again. The underlying ECM blower issue needs a technician.
Will my air conditioning still work?
Usually not while code 15 is active, because cooling uses the same variable-speed blower. Restoring the blower typically restores both heating and cooling.
Sources
✓ Verified against manufacturer service manual — March 2026