The feature in question is a warning light if two sensors disagree. You could implement that with a microcontroller, an LED and two wires. In practice, it might

The feature in question is a warning light if two sensors disagree. You could implement that with a microcontroller, an LED and two wires. In practice, it might not even require additional hardware at all. We do know in advance that its worth the cost because the cost is absolutely neglible.