Will not start and No Bus message

NATHAN POTTER

MEMBER
1999 DODGE RAM
5.2L
V8
4WD
AUTOMATIC
183,000 MILES

I have the truck listed above 1500 Sport model. I was driving it and suddenly the truck shut off all power. Then the lights came back on and the gauges were all frozen, but then reset. My ABS, airbag, check engine light, fuel, and check gauges lights all came on. The mileage started flashing and eventually started saying no BUS instead. It will crank but wont start. I tried using a scanner to read the check engine light but as soon as I plug it in, the check engine light disappears and leaves no trace, along with a couple other lights. The truck will start back up if I unplug the big white multi connector under the driver side dash near the steering column. But when the truck starts, it will start choking after about 30 seconds and shut off. I've looked up the no BUS thing and didn't learn much. The truck had just come out of the shop 2 days prior for an intake gasket replacement and I really don't want to take it back in so soon.

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1 Reply

JACOBANDNICKOLAS

MECHANIC
109,779 POSTS

Hi,

The BUS system is basically a computer area network, CAN BUS system. It ties all of the modules and computers together by using two wires. If you look at the attached two pics, it shows how the modules are all tied together via the CCD (CAN) Bus system. Somewhere there is a break down of communication. The manufacturers started this system to eliminate wiring, Basically, rather than each module having its own set of wires, they all share the same ones; hence, the computer area network (CAN). I can tell you that a "no bus" signal is usually related to the Instrument cluster signal. The Instrument Cluster (MIC) provides the CCD bus bias for the 1999 Ram Trucks. I suspect that is where the break down is, but it needs properly scanned (Can Scan or DRB3).

What I would suggest is to scan the can system which can't be done with a traditional scan tool. Here is a quick video showing how it's done. If this doesn't help, you will need to check it with a DRB 3 scan tool. This is specific to Chrysler.

https://youtu.be/InIlnsjOVFA

Let me know if you have other questions. I hope I didn't confuse you more. LOL

Take care,
Joe

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