Bottom line, if engine held at X rpm for more than Y min at < Z mph, eps light will come on (and ps won't work) until you drive more than 6 mph.

Attempted to use S to jump start my dead Inifiniti G37xS winter beater. It was emergency so didn't care this was harsh to G battery.

I just used the S to try charge G battery. I knew enough not to try and crank G while jumper cables connected. That can kill our alternator, as its asked to run other cars starter.

I was using a lithium jump pack, but G battery was so dead it wasn't enough. If I could get some charge into G battery first, then jump pack should work.

So with cables hooked up, revved S to about 3k rpm for several min. Disconnected cables, connected jump pack, G started.

Put S back in garage, but eps light was on, no ps. Uh oh, couldn't have fried anything, what happened?

The Honda maintenance manual states EPS light comes on if the car is <1 mph and rpm are >2000 for 3 mins or more.

So my holding rpm steady to charge G confused eps. But no biggie. Just driving S corrects it.

Just in case you ever run into something like this, you'll know not to worry (can imagine several scenarios where one might hold rpm for a couple min).

 

Sounds like you momentarily zeroed out the voltage to the EPS brains. Thank goodness for relearn.

 

No, I didn't.

The whole point of post was if you rev engine for minutes at a time (for some service procedure or troubleshooting or whatever), if eps light comes on you DON'T need to do a relearn.

At no point did I put any excessive loads on system that could pull S voltage down.

In holding revs up, I inadvertently tripped some programming safeguards coded into the eps system.

But just in case you really were just sitting motionless with engine revved for several minutes straight, it forgives you and turns everything back on if it then senses you are actually moving forward, presumably under its own power, at a rate consistent with engine rpm.

No relearn was required. Just drive forward.

 

Even simpler. Thanks, for the post!