OT: New but interesting car battery issue

A friend of mine has a 2012 Honda CRV. He was having an issue with the check engine light coming on due to a catalytic converter issue. That has been going on for a long time, it's not new. If he goes on long trips, it goes out, but driving around time the cat converter isn't happy.

So, I lent him my handheld code reader so he could check the codes. He told me he hooked it up, read the codes, cleared the cat code and then they car would not start. It tried to turn over, but did so just barely. He had to jump it to get it going. Then overnight it went dead again. So, he's thinking it was due to the code reader, but I'm thinking it's just coincidence and he has a bad battery, right? He drove the car around after that for a few days, without using the code reader, no problems starting.

So, he drives up here to NJ from NC and stops about 10 times along the way at rest stops, shutting the car off. Each time it starts with no problems. He gets to my house, shuts the car off and within a few mins, I hook up the code reader, read the codes, the cat code was set again, I cleared it. Then I go to start the car, and it barely tried to turn over just a bit. I was dumbfounded. Next I took a look at the battery. It looked old to me, he checked where he bought it and they say it's 3 years old. I pulled the caps off and found one cell that instead of water, had what looked like solid black crap in it. So, the battery is kaput. But the mystery remains. How could he drive around for a few days, no problems. How could he drive up here, stopping 10 times and the car starts, yet when you hook up a code reader and clear the codes, it can't start?

I thought about this awhile and the only angle I can figure is that resetting the computer causes it to somehow use more power on the next start? Like maybe it wakes up all the various electronic modules in the car to say hello, check status, etc, while it doesn't do that on a normal start? Any ideas? It's one of those mysteries that you since once in awhile.

Reply to
trader_4
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Trader,

I like your conclusion that it's a bad battery but am troubled that a 3 yr. old battery failed. Resetting the code also resets all of the computer's values to their default settings. That might make it a little harder to start but not a lot. Did you measure the battery's voltage before and after running your scanner? Your friend needs to get a new battery while he's visiting, and you should test your "code reset" hypothesis with the new battery.

Reply to
David L. Martel

trader_4, while your theory on the no-start after using the code reader is kinda out there, I cannot think of a better one. I would ask at http://hond a-tech.com/forums/ , under the CRV forum and also at

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ub.com/. Registration is free. I have not had email spamming problems from them.

I have used honda-tech.com many a time for my Civic and frequently get good responses there. I also use a specialized forum

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that I think is even better.

Reply to
honda.lioness

I didn't have a meter at the time. The fact that one cell had black crud showing at the top of the cell instead of water together with the symptoms were enough for me. But just to prove it, when we went to get a new battery, I had them load test it and it was shot.

Already did that. I should have included that with the original post. With the new battery, the car started normally after using the code reader. My friend wanted to continue on his way up the parkway to north NJ that night, another hour and a half drive. I convinced him to get a new battery right away. Friends don't let friends drive with bad batteries :)

Reply to
trader_4

Because the battery has a dead cell it's of course not going to perform correctly. The reader put enough of a drain on the battery to bring the voltage down too far to start the car. Had the weather been cold, it probably would not have started at all.

Reply to
philo

I suspect sitting with the door open long enough to reset the codes took enough power out of the battery to make it not start. 3 years is well past "average" battery life - and the Honda battery is about the size of a lantern battery to start with.

Reply to
clare

There's no mystery. Time for a battery funeral.

And after you replace the battery, check the charging system for proper voltage output.

Reply to
Bubba

Just two mins? Good grief. The car arrived after a long trip and what was done was done with the door open for two or three mins. I've never seen a situation where a battery could start a car normally, with no hesitation, no indication of anything wrong 10 times during the day, then suddenly get drained by a couple mins of open door.

3 years is

Not in my world and obviously not in the world of the battery companies who write the warranties. It's not totally unusual to see one fail that early, but it's certainly not well past average. I've never had a battery in my life where I got less than 3 years.

- and the Honda battery is about the

I agree with that, it is a small battery.

Reply to
trader_4

The reader is a small hand held device with a small LCD display. Why do you think this load is of any large consequence compared to the 1000W or so the starter takes? I've left it on other cars connected overnight with no obvious effect. It doesn't get warm, which it would if there were any significant power involved.

Reply to
trader_4

You missed the mystery part. I clearly said that I immediately diagnosed it as a bad battery. THAT wasn't the mystery.

Given that the car made it from NC to NJ just fine with a bad battery is proof enough for me that the charging system is OK.

Reply to
trader_4

Here in the real world automobile starter draw is measured in amps, not watts.

Reply to
RonNNN

In this real world, P = IV.

Reply to
Scott Lurndal

Ever hear a mechanic tell you your starter was drawing too many watts? Didn't/don't think so.

Reply to
RonNNN

What if you used the reader and then not reset the code...was it the same result, or was the reset the cause? I'm assuming with the code set, it was in a "fail-safe" or "by-pass" mode...resetting set things as normal, which they weren't.

Reply to
bob_villa

Starters are rated by the amount of power they draw. 1.0kW rating is typical for most medium-sized automobiles (if you can't do math, thats about

83 amperes at 12volts DC).
Reply to
Scott Lurndal

And in the real world, power, which is what we are talking about, is measured in watts. The claim was made that leaving the car door open for the brief perios while resetting the codes could have run the battery down enough so that it would not start. Now we could either talk about the amps drawn by the door open and for how long, how many amps the starter pulls and for how long, etc or we could talk about power. Power is more direct, so that's what I used.

Reply to
trader_4

That would have been an interesting test, but too late for it now.

AFAIK, it wasn't in a fail-safe or bypass mode. The code was for the catalytic converter not operating at correct efficiency. AFAIK, it takes something more than that for the car to give up and go into a fail-safe mode, but I guess it's a possibility, that with the check engine light on, some other unknown load gets disabled. But can't do the suggested test now, it's fixed.

Reply to
trader_4

Google this:

"how to measure automobile starter draw"

And then change the wording to:

"how to measure automobile starter wattage"

And then tell me what I said that was wrong.

Reply to
RonNNN

So that's 83 1/3 amps then? ;)

I doubt that very much.

Reply to
FromTheRafters

Why? Starters are power hogs and we wire them with 2ga or larger wire. When they rate batteries the CCA is hundreds of amps.

Reply to
gfretwell

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