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Bad electrical issue? Need help.

SDGTP99

SDGTP99

New member
Ohkay, so when I'm stopped at an intersection my cars MPH needle starts to bounce around, the radio volume goes up & down & cuts out and the battery voltage drops and if my headlights are on they dim and the car won't move. Only thing I've done to my car recently is clean the battery terminals and replace the positive battery clamp. The car was doing this every once in a very blue moon before I replaced the clamp. Now, it's getting worse & happening nearly every time I stop the car. Any thoughts, comments or suggestions are welcome. This is my DD & I need it fixed asap😅
 


Advance should be able to test it with it on the car. The reason I said that is you mentioning the voltage dropping. When voltage drops all sorts of strange things can happen to the electrical components of the car. It all goes hand in hand.
 
One more question. Can the voltage issue cause the transmission to seem to shift funny? I don't remember.
 




I've had Advance check the Alternator 2 times now and all they could tell me was something is draining the battery. At a dealership now having the PCM scanned.
 
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?
 
I agree with Stealthee. I remember you made a post about what alternator you should get and we recommended an OEM one from the junkyard but you went to advance. There should be a warranty on that so I would just make them warranty it regardless what their tests say and go from there.
 


SDGTP99 said:
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?
Click to expand...

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.
 
Also should be noted, that I have heard issues exactly like this as a result of a faulty battery current sensor (acdelco 13505369 for 5v supply from BCM, 10306471 for 10v ), it might be worth it to replace that and see if it helps with the issue, seeing as how the part is only 11 dollars.
 
Ooh I bet you're both right! A new Alternator didn't do much to fix the problems. So, I'll start by replacing that battery current sensor. Thank you!
 
Does it matter if I unplug the battery current sensor? Cuz I already did and there was no change in the cars problems.
 
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