I installed the the range active fuel management and it did exactly what it supposed to do. It immediately kept my Yukon in v8 mode. Unfortunately after a week it made my vehicle throw codes from tsp to air bag sensors etc. I called customer service and they sent a new device and I installed it ten days ago with no problems or codes as of yet. Customer service was excellent and sent me a new product overnight. I would recommend this product as auto anything stands behind their merchandise.