First id like to introduce myself, im from delaware and have a 99 3500 dually. My problem is the trans shudders alil bit around 40-50mph, i took it to the trans shop and they got 2 codes, 1693 on the engine side and 1682 on the trans side of the tester. i know the 1682 is a charging issue, coyuld this cause the trans to act up? also, when i start the truck for the first min or so, the volts read way low like at 10, then slowly rise up to above 14v, while at idle the truck will have kinda like sudden dips in the lites and the noise the fuel pump makes dip for a sec and then normal, any help would be great, looking forward to the site as well, im fairly new to the cummins. thanks!

The sudden dip of the lights is normal, that is the grid heaters. (As long as it is only for a short time.) Never heard of a lift pump doing that. Is that a stock lift pump? At start up, that seems low (10 volts) I would check to make sure the batteries are good. Have them tested. Weak batteries can give you a lot of gremlins to our trucks. Even 1 weak battery will make a difference. Also, make sure your cables are clean and tight. I have heard of guys say their trans has acted up because of a bad battery or lose connection. Also go to the "User CP" and edit your signature. Tell us everything about your truck relating to it. Mods, year, etc. Also, WELCOME to the forum. Their is a lot of knowledge that you can get from this site.

Thanks, its got the FASS fuel system in it, also has the edge attitude w outlook monitor, 5" turbo back exhuast, aem air intake. im gonna take it to a shop and have the batteries load tested today, and go over all the cables/connections as well. thanks for the info!!

P1682 Charging System Voltage Too Low Charging system output voltage low. So yes I would have the batteries load tested and the alternator bench tested to verify there abilities.

So, if my batteries and alt test out ok, what would be the next thing for me to look at?

Alternator... I would bench test it next... Then voltage drop test the main cables... http://mopar.mopar1973man.com/cummins/general/voltage-drop/voltage-drop.htm

the batteries tested good as well as the alt, but it wasnt bench tested. its really wierd, its has a "surge" at idle, a good 2volts. had a tester on the batt w it running and it read 14.1v and the surge came and dropped it to 12.2v this happens a couple times a minute. im at a total loss here fellas!!

Did you drive it to a shop to have it tested? If you did it at home and the engine was cold the drop that you saw was your grid heaters cycling.

the batteries tested good as well as the alt, but it wasnt bench tested. its really wierd, its has a "surge" at idle, a good 2volts. had a tester on the batt w it running and it read 14.1v and the surge came and dropped it to 12.2v this happens a couple times a minute. im at a total loss here fellas!!

and you are 100% sure that isn't the grid heaters in the intake. mine go off and on over and over until the truck moves 15mph or until the truck is warm.

I think it is either a draw from the grid heaters cycling on and off or the voltage regulator, which is in the PCM, isn't powering the the alternator field intermittently. Have you checked to see if the grid heater relays are are closed when the voltage falls?

do you have an automatic trans? you should change your signature to reflect your trans.there is a known problem where the alternator is old(the diodes are worn) and it WILL affect how the trans shifts(well, lockup)...search for ats fix

Edited January 6, 201015 yr by guesswho512

That ATS ground document is in the download pile already why search when its here on the site!

It has an auto trans in it. im gonna search for that ats fix here now, and i drove it to a shop so she was warmed up.