1999 Honda Accord V6 LX Automatic
​​​​​​First post on the forum

Merged onto the highway this evening and no sooner did I hard accelerate the battery, brake, and door ajar lights all came on. I read on here that it could be the alternator or the battery. Talked to a friend that's a mechanic and he suggested to go get both the alternator and battery tested, he said it could be the battery almost dead.

I proceed a few miles down the highway, everything seems to be normal with the exception of the lights. I go to the Advance Auto close by and have my battery and alternator tested. According to the tester my battery is fine, but it can't get a reading of my alternator (the test ran with the engine running). AA guy and I decide to run the test again, so I turn the engine over. No sooner do I turn the engine over and the check engine light comes on. The codes say P0705 for transmission range sensor circuit malfunction and P0505 for idle air control malfunction.

All of this happened in less than an hour. A lot of information at once and it's left me a bit stressed and kinda puzzled. If it's an IAC valve, I can just clean that nbd but the IAC is a year old and I can't imagine it being dead or clogged so soon. The transmission error I'm less familiar with. Thankfully I've gotten the car home but I'm kinda stumped.

Any help to clarify things and some suggestions of where to start would be great! Thanks in advance.

- Aaron

 

I would check the connections on your battery first.
My daughter had the exact same thing and that fixed the problem, but I think the damage was done.

When I checked the voltage with the engine running, the volts flunctuated between 13-16 volts... NOT good!

Ended up with the same issue 1 month later and I changed both the battery and the alternator. Been fine for 5 months now....

the engine codes could be a domino effect from the battery/alternator problem. Fix the battery/alternator first and clear the codes, then see how it goes.

 

I cleaned the battery contacts this morning and measured voltage when I got to work today (5 mile drive). When the car wasn't running, the battery measured 12.25 VDC. I went and turned the car on and measured....11.75 VDC.

I have an alternator coming tomorrow, I'll start with that and come back with an update soon.

 

Yeah the transmission code and the IAC shouldn't cause the engine to shut down and the dash to light up like a Christmas tree. That's an alt issue (bad internally or broken belt). Change out the alt, then pull the #13 fuse out of the right side fuse box to clear the codes, then see if any codes come back.

 

Can report that the alternator was toast, and a new one fixed it!

I got a new alternator from NAPA (BBB Industries makes them). $200. Lifetime warranty.

The other one they had was a rebuilt Denso that was $187 after core refund. The BBB was a no brainer.

Glad to find the solution so quickly!

Cheers!

 

Thanks for letting us know what the problem was.