tughillnut

well here it goes

i had a cracked head .installed a reman w/ lightning 1 injectors , and a head stud kit from haisley machine . also added a single stack kit 4" exhaust . some time during the 3-4 weeks of being in my garage (complete dead batteries) upon restart time . finally get them recharged and now here is my problem:

while driving the (ABS) and AIR BAG lights pop on intermittenly sometimes stay on, and i get a no bus in the odometer reading lcd. then all guages die but yet the truck is still running. what does this mean and how can i correct it?my super chip programmer shows no codes but the usual p2037 for low map sensor voltage. since i unplug mine. any help would be great.

i also have a superchip programmer but i un installed it because every time i put the truck in drive or rev. it would stall almost every time. not sure why maby timing or too much fuel???? but either way uninstalling it made the truck run much better. any idea why? i like using it for the tire size adj. but i can live w/ out it if the truck runs that much worse w/ it.i will just use it for the dtc codes.

given my sig what kind of hp and tq do you think i have now. i am waiting for my local diesel shop to have an open dyno day.

dieselfan

i had similar symptoms, but was throwing p1698, p 1694 , no bus. truck ran fine though. after replacing abs sensors and plug ins. i found a wire was grounding out in the engine bay, rubbing on the dipstick. dieaselfan

coalburner400

Yea... this one's a fun one. I tracked mine down to a bad ABS module. Incidentally I was able to cause the 1698 by unplugging the cluster (part of my troubleshooting). If you're getting a 1698 you might want to make sure your cluster is making good contact with the socket terminals in back.

There's a lot of info here on this problem. Do a search.

Typical causes:

Rear speed sensor (may show as a problem on your speedometer)
Front speed sensors - tone rings
Terminals (pretty much everyone in the engine compartment)
Wire that goes to the AC compressor
Gray Ground wires coming off battery
corrosion on battery terminals
loose gauge cluster
loose BCM wires, or trunk coming into the cab (lefthand side by foot)
loose steering column wire loom.

There are probably more. I'd recommend getting a bag of popcorn and a big gulp of code-red. It's always a good show working on the no-bus.

I'd advise that you start at the fuse box. Pull the fuse for the ABS to disable. Then start your truck and wait to see if the gauges work. If they do, you know its somewhere in the sensor/tone ring or module area.

Then you can go to the rear and do the same test, but with the rear sensor. Just unplug and see if your nobus goes away.

You can do the same at the BCM, PCM and remainder of the wire loom to localize the problem. Once localized look along the lengths of wire for abraded wires that have worn from vibration. Then check each terminal on the segment - use some dielectric grease while you're there.

Have fun, good luck

tughillnut

thanks guys,
I am guessing its probably a bad wire grounding out somewhere . i power washed the engine and under the body from all the oil and diesel leaking the past few months. seems like this is going to be a long process.

what does bus stand for anyway?

anyone have a link for where i can find a hard copy of a service manual? my local dealer said all they have now is a cd rom. this isnt helpful when your truck is in the garage.

is there a way to hook up a lap top to my truck for diagnostics.what program if so. any links?

thanks all!!

dodgeguy71

A bus is just a communications line more or less. Like phone lines, it allows the pcm/ecm to communicate with other modules/computers on the vehicle. In the Gm world the computers send out "state of health" signals and other computers watch for it. If a "state of health" signal is not recieved from a certain computer the one that was supposed to get the message should set a code, for example...pcm code ???? no communications with abs module or something along that line. On the GM's the no comm codes are usually "U" codes, U1000, U1016 and so on. A U1016 I believe is a pcm/ecm no communication code.

As far as hooking up a laptop, I have seen some software on the internet.....
somewhere that could be used with a laptop to check your vehicle. It was nice stuff and they really liked it...Big MONEY! Take it to a dealer, pay your $60 and let them diag it. Tell them you don't want to get it fixed and go home and buy the part, fix it yourself. That happens to me where I work upon occasion.

tughillnut

thanks dodgeguy

i was guessing it was going to be $$$$$$$$$$ i just had an x-tra laptop and was thinking it would be nice to use it but now i think diffrently!!!