Good-day Everyone

I have a 2001 Dodge Dakota, 3.9-liter engine, 45RE transmission with a little over 256,000-miles. Last night while driving it I started smelling something was burning but couldn't quite figure out what it was. The headlights started going a little dim and the battery voltage gage started showing a bit less than normal. When I finally got back home, the lights started getting dimmer and the alternator was making a whining noise which that couldn't be a good sign. I shut off the engine and restarted it and the voltage gauge didn't move and "Check Gage" light came on the instrument cluster. I shutdown the engine again and waited a few minutes and restarted the truck and it ran. After several minutes the "Check Gage" light came on again only the voltage gage didn't move during the entire time the engine was running and after a minute or so the "Check Gage" light came on again. This afternoon I tried to connect my Mini Bluetooth OBD-II CAN-BUS Diagnostic tool to see what codes came up but nothing happened. Wouldn't pull any codes. Next I tried to doing a standard code check by turning the ignition on (without starting the engine), off twice to see what code would come up. The only code that appeared was" No Bu5" in the miles indicator. All of the gages work with the exception of the voltage gage and the audible loud whining coming from the alternator. Could this mean the alternator is gone bad or is their a ground short somewhere? I replace the alternator 2 1/2 years ago because it wasn't charging and whining very loud the gage was indicating less than 12-volts at that time sort-of-similar like now. I just replaced the 12 year old battery this past February. Next question! Where do I find all of the grounding points where the ground wires located in the engine compartment verify that this isn't an issue I don't have a 2001 Dakota manual or anything that might provide some information or details where any of this stuff is located. Any insight you may have is greatly appreciated. Thanks

 

Your alternator bearings have munched themselves up. Time for a new one. If you can hear it, that's definitely bad.

 

Thanks....I wasn't sure if it was the alternator or not

 

it might also be that the diodes in the alternator and/or PCM have gone "poof". That would make more sense to cause No Bus.
In a nutshell, "No Bus" means the processor in the PCM is not properly communicating with the rest of the electronic components.

Un hook the 2 small wires going to the alternator and start the truck (if it will run at all) or see if that clears the 'no bus'.

 

Also, since you drove quite a while on battery power instead of alt power, do yourself a favor and replace the battery with a new one (I saw that you replaced it 4 months ago) when you do the alternator. If you don't think the battery was hurt, get it on a charger as soon as you can. An alternator isn't designed to charge a dead battery and doing so can kill the diodes in the new alternator so at least charge the battery back up prior to running a new alternator on it.

 

Just finished replacing the alternator a few moments ago and the battery has been on a charger for the past 2+-hours. I haven't started it yet but will in about an hour

 

I have a problem with my 01 Dakota SLT. It is the 4.7L V8 with a 5 speed manual and 183,000 miles. None of my gages work and I can't seem to find out why. The dash lights up like a Christmas tree and I receive a "no bus" in the mileage window. I have had this problem before and I fixed it by detaching the negative post on my battery and the BCM both and reconnecting all of it. I tried to do the same trick again and had no luck. Could I get some help on this? This is my daily driver and I don't want to give up a good, sound vehicle if I can help it.

 

You should make a new thread instead of posting on an old one. Make sure the ECM is plugged in correctly and doesn't have broken wires or corrosion in the connector.

 

Thanks for both bits of advice. I will check that and make a new thread.