Carrier 58MVP Error Code Code 41: Blower Outside Valid Speed Range

What Does Code Code 41 Mean?

The 58MVP uses a variable-speed blower motor that constantly adjusts its speed to maintain proper airflow. Code 41 means the motor cannot maintain its calculated speed within 10% over a 30-second period, or the speed has dropped below 250 RPM or exceeded 1300 RPM for more than 10 seconds. The control detects this mismatch and flags the fault.

The most common cause is excessive static pressure in the duct system from a dirty air filter, closed registers, or ductwork restrictions. When the motor has to push against too much resistance, it either can't reach the target speed or fluctuates as it struggles to maintain it. The control gives it time to stabilize, but if it can't maintain speed within tolerance, it flags code 41.

If code 41 persists for about 10 minutes of operation, the furnace will escalate to code 12 (blower calibration lockout). If code 41 appears together with code 44 (blower calibration fault), the problem is more likely a wiring issue between the motor and control board rather than an airflow restriction. In that case, professional diagnosis is needed.

After approximately 10 minutes of operation with fault 41 persisting. The system will escalate to error code 12 .

Common Causes

How to Fix It: Check Air Filter and Registers

What You'll Need

• Replacement air filter (if needed)
• Flashlight

Steps

1. Turn off power at the breaker or power switch AND shut off the gas supply Locate the furnace circuit breaker and turn it OFF. Find the gas shutoff valve on the supply line to the furnace and turn it to the closed position (perpendicular to the pipe). If you smell gas, leave immediately and call your gas company.
2. Check and replace the air filter Locate and remove the air filter. If it is dirty or clogged, replace it with a new filter of the same size. A restricted filter is the most common reason the blower motor struggles to reach its target RPM.
3. Open all supply and return registers Walk through every room and make sure all supply registers and return air grilles are fully open and not blocked by furniture or other items. The variable-speed motor needs adequate open ductwork to run at the correct speed.
4. Check for obvious ductwork problems If accessible, inspect the main supply and return ducts near the furnace for crushed or disconnected sections. Collapsed flex duct is a common hidden restriction that can prevent the blower from reaching its target speed.
5. Restore power and gas, then test Turn the gas supply valve back to the open position (parallel to the pipe). Turn the breaker back ON. Set your thermostat to call for heat and listen to the blower. It should ramp up smoothly to a steady speed without surging or fluctuating.

When to Call a Professional

Contact a licensed HVAC technician if:

• Code 41 returns after replacing the filter and opening all registers
• Code 41 appears together with code 44 (indicates a motor wiring issue rather than airflow)
• The blower motor makes grinding, squealing, or rattling noises
• The blower motor does not start or runs erratically
• The code escalates to code 12 (blower calibration lockout) repeatedly
• The ductwork appears undersized for the furnace capacity