solitarycheese

This started happening with my car at idle: The radio was cutting out as well. I saw the blinking EPS light a few days ago, but it went away when I shut off headlights and A/C, or when I got the RPMs up. Sometimes there was no problem at all.

Shortly after the video was taken, power steering cut out completely and the EPS light stayed lit. Next the ABS light illuminated. I limped to my parking garage and shut her off, and couldn't restart. On pushing the start button, the dash lights faded to black and didn't even get a click off the starter. My battery is only 10 months / 3000 miles old. I'm thinking its the alternator, but is there anything else I should check before ordering a new one?

Edit - after letting the car sit for about 2hrs, she started right up

S2KHANG

Alternator for sure. Easy fix

engifineer

Dont just go buy an alternator yet. You can still have a bad battery that is not accepting charge or a wiring issue. I have seen cheap batteries (aka many brands from Walmart, cheapo ones from autozone, etc) fail in a week. Never just parts swap to fix an issue (That costs more money unless you get it right on the first guess). I have seen a lot of folks on the forums spend lots of money swapping out the part that was "for sure the issue" only to find they were wrong

I ran into the same issues while driving. It started during a track night event (car started running all weird) and then all the lights started coming back on. Issue was the green connector in the back of the alternator had backed out. Old connector, clip had cracked and it just worked itself back out. It was connecting well enough to keep the charge light from illuminating, but was not charging battery. Battery was at 10.7 volts before all the lights started acting up. Charged it, fixed the connection and it was fine.

So check that you have proper connections to the alternator first. Make sure battery leads are nice and clean before testing.

Charge the battery (or use another battery if you have one) and then start the car. Use a DVM to see if you are getting over 13.5V at the battery terminals. If so, the charging system is working and you either have an intermitttent connection issue or a bad battery.

If it appears it is not charging, take the alternator off and go have it tested at an autoparts store. Most do it for free. That way you make sure your charging issue is the alternator and not something else.

engifineer

Here are the full troubleshooting pages for the charging circuit in the shop manual for he 00-05 adn 06+ models. This starts right after checking for >13.5V as I mentioned before. If you do not see that charging voltage then follow the steps in the images below before ruling it to be the alternator.You can yank the alternator and have it tested to see if that is it first. But if you have the tools to perform the below checks it will save you the trip if it is NOT the alternator but something else, or gives you the steps to test if the alternator tests good.

solitarycheese

Thanks for the replies. I have a multimeter and will check when I go home. Two hours after parking the car, it is starting up again. Very strange, the battery didn't have enough charge to start the car when I parked it, but two hours later it does?

engifineer

Batteries have some amount of recovery after they sit. So you can have one right on the edge that will not start, but may kick the engine over enough to start after a bit.

Sobe_Death

Also, if the alternator is not outputting the correct voltage, you can find regulator rebuild kits for the S2000 for much cheaper than a reman or new alternator. This usually makes everything normal again (seen very few failed bearings or brushes on Denso alternators)

solitarycheese

Ended up being a bad connection on the alternator. I had taken the alternator out previously to replace the rectifier; I guess I didn't tighten the ring terminal / screw connection enough and it worked itself loose.