Monday Morning Mice? Woes - Battery Light, CEL/ABS/VCS Lights

[SocalSam]

Was just starting my Monday activities when I noticed the battery light come on so I hurried home thinking it would strand me. Here is what I found:

14.6V at idle
12.8V battery in circuit, engine off
12.8V battery out of circuit
28VAC battery in circuit at idle??!!
28VAC battery out of circuit??!!

Battery date code is 11/2022. DC voltages look good to me. 28 VAC is whacky to me. I tested my cheapo meter and got 120VAC from a house outlet.

CEL/ABS/VCS lights came on two days ago but the car drove fine. Codes are:

C1201 - Comm error ABS
P0441 - EVAP
P0445 - EVAP
P0446 - EVAP

Mice chewed through EVAP valve connector wire which was easy enough to fix. That should take care of the EVAP codes.

Battery light still persists. Any ideas?

 

[SocalSam]

Google AI gives following result to: toyota battery light on with good voltages

What to do:

1. Check for loose or corroded cables:

Inspect the battery terminals and connections for any signs of corrosion or looseness.

2. Check the alternator:

If the battery light is on with good voltage, the alternator is likely the culprit. You may need to take it to a mechanic to have it tested or replaced.
3. Test the voltage regulator:

If the alternator is working, the voltage regulator could be failing.
4. Have a mechanic diagnose the issue:

They can use diagnostic tools to pinpoint the problem and make sure the charging system is working correctly.

 

[SocalSam]

Truck starts and drives so I went to Napa and picked up a reman Denso alternator. Good news is CEL/VSC/TCS lights did not come back. Bad news is battery light is still on.

I have the old alternator out. Found a mouse chewed wire underneath the fuse box which was a pain to splice. Hoping that is the last of the wiring issues.

 

[SocalSam]

Alternator was the cause. Battery light is out now.

 

[maxdef]

Electrical is not my area of expertise so I just want to say "thanks!" for the completeness of your post and solution. You've powered through some good stuff over the past year or so and it's breathed life into what seems like a dying forum.

 

[SocalSam]

Inspect the battery terminals and connections for any signs of corrosion or looseness.

Battery posts were clean. There was a very small amount of seepage on the top which I cleaned. On a side note, the previous owner over tightened the tie down screws which deformed the battery case. I'm thinking about replacing the battery early as I am in a single car household.