fitnessking

I have a 2005 Navigator with 68,000 miles. The 4X4 Low and 4X4 High lights flash for no apparent reason at no particular time. Typically (although not always), these are followed by the Check AdvanceTrac Light. When this happens, the speedo goes dead, I have no acceleration and I must pull to the side of the road, turn off the car and restart. Everything then seems fine until the problem recurs. This is sometimes in 10 minutes or in 3 weeks. The codes when the light is on are U1900IC and U2023 VDM. This problem has stumped 2 dealers and one independent shop. Everyone seems to think there is an intermittent short, but no one knows where. This problem first cropped up in October of 2008. For what it's worth, the battery voltage and CCA are fine. One dealer looked for chafed wires at the AC lines, but they were fine too.

Any input would be greatly appreciated. Many thanks.