I am helping a friend with his truck. He had his dead truck towed to the Stealership and was told the ECU was bad. They estimated the cost of replacment at over a grand. He emailed me and says he found a couple of ECU's on ebay for $150. I know the he needs to find one with the proper code, but I am wondering about the mileage. His truck only has 69,000 miles on it but the ECU he wants to buy says it came from a truck with 90,000 miles on it. Is the mileage stored in the ECU? If he uses theis ECU will his truck odometer show the 90,000 miles? Just want to lead him in the right direction. Thanks.