Error Code d4
Low

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

TL;DR
Code d4 means the memory card at connector P6 is corrupt, blank, or missing — but the furnace still has valid data in its microprocessor and should operate normally. A technician should replace the card to restore backup data.
Disclaimer
This article is for informational purposes only and does not guarantee the accuracy or completeness of the information provided. Always turn off power and gas supply before attempting any repairs. If you smell gas, leave immediately and call your gas company. Consult a licensed HVAC technician for diagnosis and repair. Any actions taken based on this information are at your own risk.

What Does Code d4 Mean?

Every time the Rheem R96VA0702317MSA control board powers on, it reads model-specific configuration data from a removable memory card at connector P6. This data tells the control how to operate the variable-speed ECM blower at the correct speeds for this model's specific BTU rating. When the card cannot be read — because it is corrupt, blank, wrong, or absent — the board logs code d4 and falls back to a secondary copy of the model data already stored in the IFC microprocessor. The furnace continues operating normally across all modes; d4 only appears during standby and does not interrupt heating, cooling, or fan operation.

The distinction between d4 and the more serious d1 code is that d1 means the IFC has no usable model data anywhere, while d4 means the card is unreadable but the microprocessor still has what it needs to run. d4 is essentially a data-redundancy warning rather than an operational fault.

Common causes include a corrupted card from age or a power event, a blank card from a different model accidentally installed, a card not seated fully in connector P6, or no card present at all. A technician should replace the card at connector P6 with the correct one for the R96VA0702317MSA. Using a card from a different model could cause the blower to run at incorrect speeds and potentially reduce heat exchanger life.

Common Causes

Cause Likelihood DIY?
Memory card is corrupt or blank and cannot be read Most common ✗ Call a pro →
Memory card not present but model data exists in furnace microprocessor Common ✗ Call a pro →
Wrong memory card from another furnace installed Uncommon ✗ Call a pro →

When to Call a Professional

Contact a licensed HVAC technician if:

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Sources

  1. Installation Instructions for 4 Position Condensing Two-Stage, Communicating Gas Furnaces w/ECM Blower (-)96V Series & (-)(-)96MDV Series

✓ Verified against manufacturer service manual — March 2026