My tuner got this code reading while tuning my car today. It doesn't flash the SES light, but HP Tuners references it as "Generator L Terminal P1637".

It has something to do with the alternator right? Because it takes about 10 minutes of driving or idling for the car to come to a solid volts reading. From startup until about that 10 minute mark, the Volts meter is bouncing violently from 11-15 volts.

Help?

 

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It usually is referred to the exiter wire that is on top of the alternator. There is very little slack when it comes to this wire and will look fine but the wire may be coming loose from the terminal. You can get a replacement at the dealership. They will give you one that has four wires. Just cut the ones you don't need. I've replaced it and all is fine after that..........

 

I had the alternator checked at Advance today, everything seemed good excelt they said the battery could use some charging, which wouldn't have anything to do with my situation.

I guess I'm gonna have to buy a new connector for the atl and see if that fixes it.

 

What a boner shrinker. The thing left me stranded, I'm 20 miles from home waiting for a flat bed as I am typing this out. I tried fixing a bad ground and had no luck, can't really do much until the connector and wire I bought come in the mail, and hopefully that fixes the problem. If not, I'm not entirely convinced the alternator is shot, due to it passing a charge test at Advance, so I don't know what it could be...son of a biscuit...

 

What ever happened here? I am getting the same code with no ses light. P1637. Is it the exciter wire or something else like the pcm connection or something?

 

I have the same problem with a car i'm tuning can't seem to figure it out yet

 

Its something going on with the alternator, I got this code also a few times. I had a power steering line leaking on the alternator & every time I either cleaned the p.s fluid off the alternator with brake cleaner or powerwashed the engine I would get this code & the volt gauge would fluctuate. It hasnt came back on. Does it have a p.s leak?

 

my car has had this code ever since the swap but never had any issues charging or anything

 

Well I ended up replacing my alternator (still on warranty from last year ) and it finally cleared the code and stayed off for more than a start up or two. So it's either the exciter wire or the alternator itself if this code is set I guess.

 

Sorry for not updating you guys. I first replaced the exiter wire and it didn't solve the issue. I replaced the alternator and then everything was normal again. My suggestion is to not trust the charge tests at parts stores when it's on a running engine. When I took the alternator off the car and had it bench tested, it was showing that it was dead.

 

I thought this might also be related to my security light being on, is this possible. I have this code but it does not set off the SES.
celalabama