Tired Battery=Wonky Fuel Gauge

[donjetman]

A couple of weeks ago the fuel gauge started acting wonky. After being parked for a while, at next start-up, the gauge would be on empty or full ? Eventually I got a check engine light and code P0462 = Fuel Level Sensor A Circuit Low Input.

The battery was 5+ yrs old. I tested its capacity, it was low. So, I replaced it and no more wonky fuel gauge or codes.

So if your fuel gauge starts acting wonky, check the battery.

 

[intheburbs]

Low voltage wreaks havoc on lots of systems.

 

[Marky Dissod]

Low voltage wreaks havoc on lots of systems.

The ecm and tcm even have modifiers written into them specifically in case battery voltage gets under certain thresholds.

 

[Geotrash]

The ecm and tcm even have modifiers written into them specifically in case battery voltage gets under certain thresholds.

Good call. Because the various sensor voltage ranges would be off, requiring different calibrations. But I would wager that other systems not tied to adjustable tables in the ECU would be the ones to throw codes when the voltage is low.

 

[Marky Dissod]

Good call. Because the various sensor voltage ranges would be off, requiring different calibrations.

Not only sensors / inputs. Biggest concern would be injectors, which can get pretty complicated.
To oversimplify, once a battery is weak enough, it can act like a rev limiter / valet mode.
I know from experience, I've had alternators die on me in several cars (why I still fantasize about adding solar panels to my Tahoe ...).

 

[j91z28d1]

I'm not sure if there's a correlation but it sure seems like the newer vehicles that have all the battery monitor programing and sub routines that change voltage output. react way worse to a battery getting weak then the cars without it, that just have a dumb alt that puts out a constant voltage. even if they have the same number of modules and stuff

 

[Down8]

Not only sensors / inputs. Biggest concern would be injectors, which can get pretty complicated.
To oversimplify, once a battery is weak enough, it can act like a rev limiter / valet mode.
I know from experience, I've had alternators die on me in several cars (why I still fantasize about adding solar panels to my Tahoe ...).

I've been looking at tossing something like this on my rear driver's side window (can't see out of it anyway). The 12V plug could (maybe/theoretically?) go right into the one in the luggage area.

https://www.amazon.com/dp/B0BMZQ8VN5/

-bZj