Is a battery charging update needed?

October 30, 2023

#20

Oct 6, 2020
(Edited)

The comments about the ECM software controlling the alternator, and the damage to the battery are correct. For a little mpg saving, Subaru has put their owners at risk of getting stranded, as well as needing to replace batteries much more often than should be. Also, as mentioned, turning on the lights (parking lights are enough, headlights not necessary) will be a simple work-around for this misguided “feature.”

After getting stranded twice, and putting in new batteries, I started monitoring the system voltage. As others have reported, it initially comes up to about 14.4 V, then after some time drops below 12 Volts (as low as 11.1) even during highway driving. This is ridiculous, and definitely the reason the batteries failed.

Going back to the dealer (for the exhaust system recall) I insisted they put in the ECM update. It was free, as it should be to correct their mistake, and now the voltage is a steady 14.1 V at any speed.

I think this should be a general no-cost update to all their vehicles. If not a full-scale recall, at least a general corrective measure when any vehicle enters their shops.

BTW, this alternator control system is not unique to Subaru. It is a commonly used “trick” by many manufacturers these days to squeeze a little more mileage. Unfortunately, it comes at the expense of leaving drivers stranded as well as needing to buy many more battery replacements than is normal.

Source link