gaurangnaik90

Hi,

I own a 2010 Honda Accord 3.5L-V6. Two days back, the battery light on my dashboard came on and the battery (and the car) died on the road. I got the car towed to my mechanic, who said the alternator malfunctioned and hence, replaced it. After the new alternator was installed, I took the car for a test-drive and everything seemed fine at first. The battery light was gone. But as I reached my building's parking lot, the battery light came on for a second and went off. I rushed to the mechanic and on my way to the mechanic, the battery light came on and disappeared several times. However, it never came on at the mechanic's. He said everything had tested just fine after he installed the alternator and suggested that I drive around the car a little and come back if the problem persisted.

At this point, I decided to check a few things myself. I checked the battery voltage when the car wasn't running. It was 12.6V. Then, as I started the car, the voltage would drop to 11V and then stabilize at 14.4-14.5V. With most appliances switched ON (AC/radio/headlights), the voltage would drop to ~13.5V, but the battery light never came on. The drop across the alternator terminal and the battery positive was 0.1V (same as across the battery negative and chassis). These looked within the normal range from what I read online so I took my car for another test run. The battery light came on several times. Almost all of these times, I was coming to a stop at the red light/stop sign. It occasionally came on while I was driving in stop and start traffic. It never came on when I was driving above 30mph (rpm over 1500). The light doesn't switch on when I have my car on Park and brakes applied. It only came on when I am stopping at red lights (stopping from ~35-40mph to 0) and that too, not every time. Each time the light would go away in a second or two. Moreover, if the light is on, it turns off as soon as I switch to Park from Drive. I read some posts that suggested that the belt connecting the alternator and the engine could be slack but that is not the case either. Someone suggested that the battery connections could be loose and so I tightened all the visible connections.

Since my mechanic was closed today, I went to Advance Auto and had them run their free battery/alternator diagnosis. Nothing out of the ordinary showed up in their diagnosis either. While returning home, the check engine light turned ON. The code is P0240. Since then, I haven't seen the battery light come on but I have driven for only about 5 miles. It doesn't seem like the two problems are related but could they be? I am going to take my car to the mechanic first thing tomorrow but I was hoping to get some ideas. I typically do just as the mechanic says and I go to the same mechanic always. I just want to be a little more informed this time around since the alternator itself set me back by $600. I am looking for any help I can get.

PS - As I mentioned, the alternator was replaced two days back (I am not sure which brand). The battery was replaced just over a month ago. All six spark plugs and one ignition coil were replaced about 4 months back.

Thanks,
GN

Scottwax

Ever check the belt? A lose belt can cause issues. Or there might be an intermittent short in the new alternator.