Rheem R96VA0702317MSA Error Code d4: No Valid Model Data on Memory Card

What Does Code d4 Mean?

Code d4 (No Valid Model Data on Memory Card) is a non-critical fault on the Rheem R96V Integrated Furnace Control (IFC). Every time the board powers up it looks to the small model-data card plugged into connector P6 for the airflow tables and blower profiles that run this variable-speed ECM furnace. When that card is unreadable — corrupt, blank, the wrong card, or absent altogether — the IFC posts d4 but falls back to a valid copy of the model data already held in its own microprocessor. Because that backup copy is intact, the furnace continues to operate normally in every mode, and d4 is only displayed during standby.

The key distinction is between d4 and the critical d1 (No Model Data) code. With d1, no valid model data exists from any source, so the furnace is completely shut down. With d4, the card cannot be used but the microprocessor still has what it needs, so heating, cooling, and fan all keep working. In effect d4 is a data-redundancy warning rather than an operational failure — the furnace is fine right now, but it has lost its backup card.

Common causes are a card that has become corrupt, a blank card, a wrong card carried over from another furnace, a card not fully seated in connector P6, or no card present. Because the microprocessor is carrying the load, there are no performance symptoms; the only outward sign is the d4 reading in standby.

The reason to act is that the backup matters later. If the IFC is ever replaced and there is no valid card to transfer, the new board would come up with no model data and post d1 — a full shutdown. A technician should install the correct model-data card for this specific furnace at connector P6 so a valid backup is on hand. Using a card from a different model can produce a horsepower mismatch (code d6) or incorrect blower behavior, so the card must match this model.

What You'll Notice

• The furnace heats, cools, and runs the fan normally with no change you can feel
• The IFC dual 7-segment display shows d4 only while the furnace is sitting in standby (not during an active heat or cool call)
• The code appeared after a recent service visit, board work, or a power event
• Inspecting the board reveals the model-data card at connector P6 is missing, loose, or was swapped
• No lockout, no odd noises, and no loss of comfort accompany the code

Common Causes

How This Is Diagnosed

A technician confirms the furnace is still operating normally, which distinguishes d4 from the shutdown code d1, then inspects connector P6 to see whether the model-data card is present, fully seated, and the correct card for this model. The card is checked for corruption or for being blank or mismatched. Because the microprocessor's backup copy is what is keeping the furnace running, the corrective action is to fit the correct model-data card at P6 so a valid backup exists, then clear the code.

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 d4 reading appears in standby and you want the correct model-data card installed before any future board replacement makes it necessary
• The card at connector P6 is known to have been swapped or is from another furnace
• A control board or memory card was recently replaced and you want to confirm the card matches this exact model
• You want to preserve a valid backup card so the board does not come up with a d1 shutdown if it is ever replaced

✓ Verified against manufacturer service manual — March 2026