2013 Accord EX Battery or Alternator?
 

Last week I had to have my transmission speed sensor replaced. Speedo/Odo stopped working, got dashboard lights and a code flashing on my dash. That seems to have been fixed by replacing the sensor.

However the next morning it wouldn't start. I jumped it and let it run for an hour or so. Still wouldn't start on its own. So it took it to AutoZone and had them test the battery. They said it was dead and replaced it. I asked them to check the alternator and they said it was bad too. However there is no battery light showing on the dash. Now its sitting in my driveway with the new battery disconnected while I decide what to do.

FYI, I bought it for my son a couple of weeks ago from a reputable local non-affiliated dealer. It has 64k miles on it. He paid to have the speed sensor replaced even though he really didn't have to.

Anyway the dealer mentioned a recall on the battery management sensor. Honda doesn't have my VIN listed in that recall so I'm a bit doubtful about that.

So...I'm just looking for advice. I've been a Toyota guy for years - this is my first Honda. Do I trust the AutoZone guy and take it to the shop or do i risk damage to the new battery by a bad alternator?

Are you having a crank/no-start or a no-crank/no-start. Crank means that when you turn the key to start the engine, the starter motor spins the engine.

It just clicks and the dash lights flash. Not even trying to start.

Let me clarify. It starts with the new battery. My worry is if i use the car with the new battery it might damage the battery.

Something drained the battery. It could have been a bad battery or something else draing current. You can look for a parasitic draw with a digital volt/amp meter to figure out if/why you have a current draw. Search Youtube for videos on how to test. Pine Hollow Diagnostics on YouTube has some good videos on this.

Let me see if I understand this correctly , car starts fine now with new battery but since Auto Zone told you that you have a bad alternator , your concern is that if
you drive the car with a bad alternator it might cause damage to the new battery ,,assuming I'm understanding it right that is what worries you .
If you don't put much trust in Auto Zone I would have a reputable shop test the alternator that way you will know for sure

If you have a volt meter and know how to use it, it's very easy to check if the alternator is working. Look for 14 or so volts when the car is running at the battery terminals.. Not more than 15v or you could have an overcharge situation. Usually a dash light will also indficate no charge from the alt.

With the car turned off a new battery should be close to 13 volts. Make sure it's not dropping quickly with the car off - not running or you may have a parasitic drain.

All new cars use battery current when turned off to power things like anti theft...ect..

Also some pcm/ecm's can turn off the alternator if it decides the alternator has fully charged the battery.

I've never had Autozone...ect tell me my battery was good. They have always wanted to replace it. You may have a bad Alternator that didn't charge the battery, so it was dead but not officially "Bad" Now you have a new battery so check the alternator. If you don't know how take it to more than 1 place. O'rilleys, Advanced auto.... even better is a quality mechanic.