- Dec 12, 2014
- 1
Have an 08 trailblazer at startup everything is fine. Once u drive down road and hit about 30 mph or 3rd gear, service 4wd light comes on. While driving if move selector switch to auto it will blink and take while to transfer but does sometimes have to slow down to do it. Now once in auto mode if u stop and start out and make turn its in 4wd even though auto mode is still selected. I know from the binding or hop so to speak. Now at this time stabiltrak light comes on also. Once stabiltrak light comes on you can't switch out of auto mode until shut truck off if u move selector switch once in auto mode it won't do anything auto mode light just stays solid no ther lights flashing when u move to another mode like 2wd. Once you shut truck off and restart it will read in 2wd drive mode and no service 4wd light on until hit about 30mph and light will come every time. If u start vehicle and select any modes auto, 4hi, and 4lo it will make every selection and encoder and actuating motor will work as supposed when making each selection and no service 4wd drive light on until u drove and hit 30 mph. Pulled codes and have c0455 stabiltrak c0300 rear props haft or speed sensor and c0374. I'm leaning toward rear speed sensor, bad connection , encoder motor position sensor or even tccm reprogramming. I believe tsb about c0300 and c0374 and with both codes could need tccm reprogramming. I've been doing some searching and have found couple others having same issues only to se no answers to problem. My questions are can you test speed sensor to see if bad and if so what readings should I have on my multimeter and could encoder motor position sensor be possible cause. I think c0455 steering wheel position sensor is present because stabiltrak light coming on. That light only comes on when you put in auto mode and start out making a turn. Any other time your driving and 4wd service light on the stabiltrak light is not on. Sorry for long post, just trying to put as much info about problem as possible.