Go to your favorite Auto Store and have them read the code. Limp mode usual indicates it is not getting information it needs. I bet the speedometer gets its information from the speed sensor and if it looses that it will go into limp mode as it has no idea how fast your are going.started at 150k miles now have 190k miles speedometer sometimes wont work and less then a minute later car goes in limp mode and cel comes on. does this a couple times a week driven daily. should i worry?