I just bought a 2024 F250 new a couple months ago. I put a 2” level on it and 37” tires. A couple weeks ago I had a pre-collision fault error so I took it into a ford dealership. They said I voided the warranty by putting 37” tires on it and they can’t fix the issue but still charged me $200 diagnostic fee. Is this normal? I called ford customer service and they talked to the service manager and confirmed the “aftermarket” tires caused this. Any idea how to fix it?

 

Return the truck to how it was built

 

Under the Magnuson‑Moss Warranty Act, a manufacturer cannot deny warranty coverage simply because a vehicle has been modified—unless the manufacturer can prove the failure was caused by that modification.

1. Burden of Proof for Denial

• According to the FTC and interpretive guidance, a manufacturer must demonstrate that the malfunction was directly caused by an aftermarket modification before denying warranty coverage.
  • For instance, installing a cat-back exhaust doesn’t allow denial of unrelated failures, like an infotainment screen, since there's no causal link. [engineerfix.com]

2. Legal Text – 15 U.S.C. § 2307(c)

• The Act states that a warrantor is not required to honor the warranty if the defect was caused by:
  “damage (not resulting from defect or malfunction) … or unreasonable use (including failure to provide reasonable and necessary maintenance).” [govinfo.gov]
  Modifications fall under “damage … or unreasonable use” only if they actually caused the failure.
  

🔍 How It Applies to Modifications

• Unrelated mods (like cosmetic or performance tweaks):
  • If these mods did not cause the specific failure, the manufacturer cannot legally deny warranty for the affected part.
• Related mods (like engine remapping or overloaded systems):
  • If there's clear causation—e.g., an ECU tune caused a transmission failure—the manufacturer can deny warranty for that specific damage.

🔑 Summary

• The Magnuson‑Moss Warranty Act protects vehicle owners:
  • Blanket denial of warranty is not allowed just because of modifications.
  • Denial requires proof that the mod directly caused the failure.