Rheem R96VA0702317MSA Error Code d6: Horsepower Conflict on Memory Card

What Does Code d6 Mean?

Code d6 (Horsepower Conflict on Memory Card) is a non-critical fault on the Rheem R96V Integrated Furnace Control (IFC). This furnace uses a variable-speed ECM blower motor that reports its own horsepower rating to the control board. The IFC compares that reported horsepower against the value stored in the model data on the memory card at connector P6. When the two do not agree, the board posts d6. Crucially, the model data held on the IFC microprocessor does match the installed motor, so the furnace continues to operate normally in every mode and d6 is only displayed during standby.

This makes d6 different from the two other memory-card codes on this board. Code d1 (No Model Data) is a full shutdown because no usable model data exists anywhere. Code d4 (No Valid Model Data on Memory Card) means the card cannot be read at all but the microprocessor's copy keeps the furnace running. d6 is narrower: the card can be read, but the specific horsepower figure it carries conflicts with the actual blower motor — while the microprocessor data still matches that motor, so operation is unaffected.

The usual cause is a parts substitution. Most often the blower motor was recently replaced with one of a different horsepower rating than the card expects; less often, the memory card or the control board was replaced with one intended for a different model. Because the two-stage ECM blowers in this furnace family come in different horsepower ratings to suit each model's airflow and BTU capacity, mixing parts across models produces exactly this conflict.

Although the furnace runs with d6 active, the mismatch should be resolved. A motor whose horsepower does not match the model's design can move the wrong amount of air, which can under-cool the heat exchanger over time. A technician should verify that both the installed blower motor and the memory card are the correct parts for this specific model and correct whichever one is wrong.

What You'll Notice

• The furnace heats, cools, and runs the fan with no obvious change in comfort or performance
• The IFC dual 7-segment display shows d6 only while the furnace is in standby
• The code appeared after a blower motor replacement or after control board / memory card service
• There is no lockout and no repeated cycling — just the standby code
• Airflow may feel slightly off if a mismatched motor is moving more or less air than intended

Common Causes

How This Is Diagnosed

A technician confirms the furnace is still operating normally, which separates d6 from the d1 shutdown, then reads the horsepower the blower motor reports and compares it with the horsepower stored on the memory card at connector P6. Because the microprocessor data matches the motor while the card does not, the technician determines which part was substituted — most commonly a blower motor of the wrong horsepower, or a card or board from a different model — and replaces whichever part is incorrect so all three sources (motor, card, and microprocessor) agree for this model.

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 d6 code appeared after the blower motor was replaced, suggesting the new motor's horsepower does not match this model
• The memory card or control board was recently swapped and may be from a different model
• Airflow seems stronger or weaker than before even though the furnace still runs
• You want the motor and memory card verified as the correct parts before a mismatched blower stresses the heat exchanger over time

✓ Verified against manufacturer service manual — March 2026