Can the ECM be adjusted or does it need replaced (ouch).
Between this post and your other ones it REALLY Sounds like your dealership service manager just wants to charge you for throwing parts at your truck without actually diagnosing the problem.
While it is good that you are trying to learn more about your truck by asking questions here, it also sounds like you need to find another smarter and likely more honest repair shop.
That said, in order for members here to help out, you need to be MUCH more detailed in your description of the truck AND the description of the symptoms it is experiencing.
Firstly PLEASE fill out the year and fitment of your truck as well as its ownership history if possible
With the added details of your truck and symptoms we can offer you much more detailed answers as to what the problem and solutions might be…rather then just stabbing in the dark like your dealership seems to be doing
No PCM on his truck. The ECM controls the voltage.The ECM does not regulate alternator voltage - it is done through the PCM.
There is a battery temperature sensor under the driver side battery that helps control the upper limit of the voltage regulator setting. Battery voltage at 14.5 volts on a 30° day COULD BE NORMAL. The same reading on a 80° day would be excessive. The dealer should and probably does know this.
I think it would be worth your time to look up a discussion overview of how a charging system works on your era of truck. There is good information here on the TDR regarding that subject, as well as on the internet. At minimum it would help you ask us or the dealer or any repair shop the right questions. It would also help put you at ease regarding what is normal and what is not normal.
- John
No PCM on his truck. The ECM controls the voltage.
Well I didn't mean to start a fire here. ECU/ECM/PCM/ all refer to something I can't fix or adjust. However reading back over many old posts it seems 14.5+- at the batteries with my fluke meter is normal. I appreciate the help.My bad - thanks for the clarification. That's what I get for not researching before I post.
- John