Quote Originally Posted by SDGTP99 View Post
Ok so. Finished the scan & the only current codes are for Tire Pressure Sensors. In History however I had U1000, U1301, U1096, U1088, & U 1064. I looked up those codes and couldn't find out what they mean. My car now experiences all these problems while driving and shifts funny frequently. So is my problem really an Alternator going bad & it's just not testing bad?
Electrical issues can cause funny things to happen, the U codes are "universal" codes, often times MFG specific codes, but typically are an indication of data communication errors, and often times a result of rapid voltage fluctuations (voltage drop and restart of the module) or the imminent failure of a module or ECU. U1301 is a Class 2 circuit short to battery, U1000 is a communication failure between the ECU, U1096 is loss of communication with the instrument cluster, U1088 seems to be related to invalid data from a suspension control part, likely the stability control (EBCM), U1064 Loss of Communications with DIM.

Check your battery voltage with a multimeter with the car not running, if your less then 12.5v @ rest, replace it, if you have access to a load tester, be a good idea to see if its able to support the proper amount of cranking amps, and making sure the battery doesnt have a bad cell. The voltage regulator in the alternator could be problematic yes, but generally speaking they dont cause these codes, these are a result of a dead short in the system somewhere causing communication failures.