1999 Dodge Dakota sport no bus
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From: Danville, KY
1999 Dodge Dakota sport no bus
1999 Dodge Dakota sport:
3.9 l v6
Automatic transmission
Four-wheel drive
183,000 miles
About about 7 months ago and my truck died while I was going down the road, and after pulling over to the side of the road and setting for a few minutes I noticed that my odometer flashed five times and then it gave me a no bus reading. all of my gauges were at 0 if said no bus in the odometer area and all of my check engine lights were on. I wiggled the connector to the PCM that's closest to the firewall just trying to check and see if there was a short and sure enough I heard my fuel pump kick on and all of my gauges came back on. flash forward six months and it had happened a number of times, each time I would wiggle that connector and everything would come back on and I'd be able to drive for another week or two before I would have another episode. then one day it died on me and no amount of wiggling my connector would cause it to come back on so I had to have the truck towed back to my house and there she said for a month while I start digging online. after contacting my local Dodge dealer, the only other Dodge dealer was over two hours away, I was told that that would have to pay $140 for a diagnostic fee before they would even talk to me about what could be wrong. so I talked it over with a mechanic friend of mine who told me it had to have been a short in my harness or my PCM. I took it up to his shop and a half hour later he had hooked upmy harness to his computer and showed that I didn't have a drain anywhere in my system so it was less likely to be a short. This let us both to believe that it was my PCM. so I went online and ordered a new PCM which require my VIN number and my mileage and 6 days later it arrived in the mail. I followed the instructions that came with it to the letter and started the truck up. It ran fine for the first couple of hours until I had to make a run to town. on the way down the road all of my gauges zeroed out all my check engine lights came on and I got the no bus signal again. but this time the truck did not die didn't stutter did not start running rough it shifted just fine and for all intents and purposes was running as if the computer was still active. now as soon as I get in the truck and turn the key over I get a no bus at my odometer all of my gauges are zeroed out to bottom all of my check engine lights are on but the truck will start and run just fine.
do any of you have an idea about where I could start to diagnose this problem as I'm kind of iffy on continuing to use it as a daily driver if a short somewhere in the harness could fry this new $300 computer.
Thanks in advance.
3.9 l v6
Automatic transmission
Four-wheel drive
183,000 miles
About about 7 months ago and my truck died while I was going down the road, and after pulling over to the side of the road and setting for a few minutes I noticed that my odometer flashed five times and then it gave me a no bus reading. all of my gauges were at 0 if said no bus in the odometer area and all of my check engine lights were on. I wiggled the connector to the PCM that's closest to the firewall just trying to check and see if there was a short and sure enough I heard my fuel pump kick on and all of my gauges came back on. flash forward six months and it had happened a number of times, each time I would wiggle that connector and everything would come back on and I'd be able to drive for another week or two before I would have another episode. then one day it died on me and no amount of wiggling my connector would cause it to come back on so I had to have the truck towed back to my house and there she said for a month while I start digging online. after contacting my local Dodge dealer, the only other Dodge dealer was over two hours away, I was told that that would have to pay $140 for a diagnostic fee before they would even talk to me about what could be wrong. so I talked it over with a mechanic friend of mine who told me it had to have been a short in my harness or my PCM. I took it up to his shop and a half hour later he had hooked upmy harness to his computer and showed that I didn't have a drain anywhere in my system so it was less likely to be a short. This let us both to believe that it was my PCM. so I went online and ordered a new PCM which require my VIN number and my mileage and 6 days later it arrived in the mail. I followed the instructions that came with it to the letter and started the truck up. It ran fine for the first couple of hours until I had to make a run to town. on the way down the road all of my gauges zeroed out all my check engine lights came on and I got the no bus signal again. but this time the truck did not die didn't stutter did not start running rough it shifted just fine and for all intents and purposes was running as if the computer was still active. now as soon as I get in the truck and turn the key over I get a no bus at my odometer all of my gauges are zeroed out to bottom all of my check engine lights are on but the truck will start and run just fine.
do any of you have an idea about where I could start to diagnose this problem as I'm kind of iffy on continuing to use it as a daily driver if a short somewhere in the harness could fry this new $300 computer.
Thanks in advance.
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Joined: Apr 2010
Posts: 87,479
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From: Clayton MI
It's possible that the 'new' computer you got, also has issues. None of them are new, they are remans.... and some folks remans simply aren't that good.....
Could try an experiement..... WHen the No Bus come up on the odometer, start unplugging sensor on the 5 volt bus. (which is basically all of them.....) Unplug a sensor, see if the dash comes back. (engine does not need to be running) O2 sensors are famous for causing this type of failure, but, any of them could be doing it. The fact that the engine still runs decent though, leads me to believe that it is NOT the crank, or cam sensors.
Could try an experiement..... WHen the No Bus come up on the odometer, start unplugging sensor on the 5 volt bus. (which is basically all of them.....) Unplug a sensor, see if the dash comes back. (engine does not need to be running) O2 sensors are famous for causing this type of failure, but, any of them could be doing it. The fact that the engine still runs decent though, leads me to believe that it is NOT the crank, or cam sensors.
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Registered User
Joined: May 2020
Posts: 4
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From: Danville, KY
It's possible that the 'new' computer you got, also has issues. None of them are new, they are remans.... and some folks remans simply aren't that good.....
Could try an experiement..... WHen the No Bus come up on the odometer, start unplugging sensor on the 5 volt bus. (which is basically all of them.....) Unplug a sensor, see if the dash comes back. (engine does not need to be running) O2 sensors are famous for causing this type of failure, but, any of them could be doing it. The fact that the engine still runs decent though, leads me to believe that it is NOT the crank, or cam sensors.
Could try an experiement..... WHen the No Bus come up on the odometer, start unplugging sensor on the 5 volt bus. (which is basically all of them.....) Unplug a sensor, see if the dash comes back. (engine does not need to be running) O2 sensors are famous for causing this type of failure, but, any of them could be doing it. The fact that the engine still runs decent though, leads me to believe that it is NOT the crank, or cam sensors.
Administrator
Joined: Apr 2010
Posts: 87,479
Likes: 4,223
From: Clayton MI
It is most likely that just one sensor is causing the trouble, so, you do indeed want to unplug them one at a time. A quick list off the top of my head:
TPS
MAP
ECT
O2 sensors
IAT
crank and cam sensors as well, but, your truck runs, so those are probably not the problem.
I am probably forgetting one or two...... Maybe someone else can add to the list.
Idle air control solenoid is 12 volts, so, not on the 5 volt bus.
TPS
MAP
ECT
O2 sensors
IAT
crank and cam sensors as well, but, your truck runs, so those are probably not the problem.
I am probably forgetting one or two...... Maybe someone else can add to the list.
Idle air control solenoid is 12 volts, so, not on the 5 volt bus.
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Joined: May 2025
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I know this is an old thread, but I had the same problem. It turned out to be a short in the 5 volt line. I found it by stripping the wires in the computer and measure for 5 volts, did not have it, cut the wire and 5 volts came back. problem was a short in the harness above the transmission.