2004 honda civic LX battery light and car stalling

So my 2004 honda civic LX with 165k miles has had some battery issues, or so it seems. While driving the car has been “shutting down”, headlights fail, dash lights fail, radio sound goes off, and sometimes the car stalls. Typically this is happening when in stop and go traffic. The battery light on the dash comes on and off during these moments of failure. These issues started a few months ago when the dash maintenance light came on. I brought the car to a mechanic to see if he knew the issue. We decided to test the alternator and it was fine but we replaced it anyway. The issue went away until recently when the maintenance light came on again and seems the problem is worsening this time around. It seems like another trip to the mechanic is in store but if anyone has any thoughts, I am all ears. Thanks!

–Dan

How old is the battery? Are the battery connections clean and tight? Check the engine and chassis grounds are tight and clean.

Is it some sort of maintenance light that is coming on or is it your check engine light?

I’ve had vehicles with a maintenance light, that tells me to change the oil or provide some sort of maintenance but is not a trouble indicator.

If it’s the check engine light then you need to get the codes read to see what the car is trying to tell you.

Not sure that the battery light coming on is a symptom or just a result. As the car begins to stall I could see the engine speed getting low enough to stop the alternator from charging, that would kick on the battery light.

Get a plug-in voltmeter like this one:

Your Civic has a 2-stage alternator charging system. The meter should read ~12.6V when your key is first turned to AUX, then 13.8-14.5V after it starts. After the battery has been recharged sufficiently while driving, the meter will alternate between 12.8 and 14.5 or so volts. Anyone suspecting charging system issues should know what their battery voltage is doing.

Get the battery load tested and have the battery terminals cleaned. Since the check engine light is coming on (I assume this is called the maintenance light on your car) , there must be diagnostic codes so get those read. That will provide some clues. Also its possible the battery light is coming on b/c the engine is about to stall, and it has nothing to do with the battery or the charging system. A faulty idle control, dirty throttle body, clogged engine air filter, etc. could cause that. Is all the routine engine maintenance suggested in the owner’s manual up to date?

As @Knfenamore mentioned…how old is the battery?
Did the mechanic test the battery too?

Battery connections are the first place to begin when you have a “No start” situation. Even
if you have a new battery, if the connections are loose, dirty or corroded, you will not be
allowing the full flow of current to pass thru the connections. The connection may be
enough to turn on the lights, but not enough for the huge flow that is needed to operate the
starter. This is where many people say that they know the battery is good….”because the
lights come on”. This is no more a battery test than licking a 9volt battery. It only tells you that there is electricity…not how many volts or the amperage that flows from the battery.
Jump starting may have wiggled the terminal just enough to allow the current to pass and start the engine, but tomorrow you have the same problem.

First remove the cables from the battery and use a wire brush to remove any corrosion and dirt from the battery posts and the cable terminals. There is a tool with a round wire brush for this purpose, found at any auto parts store for less than $10 http://shop.advanceautoparts.com/p/kd-tools-terminal-battery-brush-kdt201/25980576-P?searchTerm=terminal+brush.
Before connecting the cables, apply a coating of di-electric grease to the battery posts this will keep oxygen away from the connection so that it will not corrode as fast.

It is just as important that the other end of the cables also have a clean connection. Remove the positive cable from the battery again so that you do not short anything out. Follow both cables to their far ends, remove this connection and wire brush the connection and the cable terminal clean and retighten these connections.

If there was work done recently, there may have been an “engine to body” ground that was not installed following the work. These grounds normally run from the rear of the engine to the firewall and are uninsulated and most are a braided wire. If any of these are found unattached…reattach them.
Remember….this is not a “Sherman Tank” don’t over tighten the connections.
Tight…tight………………too tight…broke!!!

Yosemite