Vehicle is overcharging

AUSTINO

MEMBER
2003 JAGUAR S-TYPE
3.0L
6 CYL
2WD
AUTOMATIC
67,000 MILES

Good afternoon, my vehicle is overcharging. Do you know what can cause this to happen?Thank you in advance.

Sunday, June 28th, 2020 AT 10:07 AM

6 Replies

KASEKENNY

MECHANIC
18,907 POSTS

When you say it is overcharging, what is the actual voltage it is charging when the engine is running?

Take a look at this information. The ECM will target 14-15 volts and will back it down to 13.6 volts when needed. Let's start with what the voltage is and go from there. Thanks

Image (Click to make bigger)

SPONSORED LINKS

Was this

answer

helpful?

Yes

Sunday, June 28th, 2020 AT 4:49 PM

AUSTINO

MEMBER
209 POSTS

Thank you for that information. Yes, it is over charging when the engine is running and also the acid from the battery is leaking out.

Was this

answer

helpful?

Yes

Monday, June 29th, 2020 AT 7:20 AM

KASEKENNY

MECHANIC
18,907 POSTS

Okay. Clearly we need to replace the battery but again, we need to find out the exact voltage it is charging. There is a chance that the PCM is trying to raise the voltage due to the battery so I would replace the battery due to the leaking and retest the alternator output.

Here is a guide on how to test the alternator:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Was this

answer

helpful?

Yes

Monday, June 29th, 2020 AT 8:03 PM

AUSTINO