[ddgeramcharger79]

Got a 99 Dodge Ram 1500 for a steal of a price.. runs and drives great until the ecm starts to get some heat and then it throws out the "no bus" code until you get underneath and jiggle the plug.

Anyone know if they ever made a good replacement ecm that could withstand the heat from being in the engine compartment? I don't wanna buy a junk computer that's just gonna fall apart again

Also thinking about building into the system my own version of a small computer fan 

 

[comrade cheddar]

  Are you sure it's the ecm that is causing the issue? The bus signal is low voltage/ low amps. Any resistance from a loose or corroded connections to a bad wire or component  can screw up the signal.

 

[KThaxton]

I've never heard of them having any kind of heat-sensitivity issues. I had the ignition portion of my PCM fail in my 2000, I bought one from Autozone and it lasted many years and was still in use when I sold it.

 

[ddgeramcharger79]

Are you sure it's the ecm that is causing the issue? The bus signal is low voltage/ low amps. Any resistance from a loose or corroded connections to a bad wire or component can screw up the signal.

I took the connection loose and it's nice and clean. When I wiggle the plug just a bit the no bus goes away and it fires right up.. never really does it when it's cold just after the engine heats up and the engine compartment gets hot

 

[ddgeramcharger79]

I've never heard of them having any kind of heat-sensitivity issues. I had the ignition portion of my PCM fail in my 2000, I bought one from Autozone and it lasted many years and was still in use when I sold it.

Is it located in a different location from the ecm?

 

[comrade cheddar]

  The connection can be corrosion free and still have issues. Have you properly checked the pin fitment?  Are the wires tight in the connector.  Maybe where the connector enters the ecm there is a bad solder joint. I've seen many time where a module was replaced and the problem is still there.

 

[ddgeramcharger79]

The connection can be corrosion free and still have issues. Have you properly checked the pin fitment? Are the wires tight in the connector. Maybe where the connector enters the ecm there is a bad solder joint. I've seen many time where a module was replaced and the problem is still there.

I'll give everything a really good look over again. I cleaned the plug out and checked the pins quickly but if it saves me 200 bucks I'll gladly look over the pins some more lol

Guess I should also clarify it is the PCM that I mess with the under the hood. The three plug pcm bolted to the firewall

 

[ddgeramcharger79]

I took the plug apart and checked everything... all seems well the pins all look good and everything looks clean and tight. Soaked it down with some wd40 and hooked it back up. Haven't had anymore shut downs since then but they have been very random when they do happen.

 

[ddgeramcharger79]

Well.. died again randomly.
Step out the truck press gently on the plug and it fires right back up. I couldn't see anything at all wrong with the plug itself or the pins on the pcm.

 

[comrade cheddar]

  You will never "see" anything wrong with the plugs. Find a pin the same diameter as the trucks pins and feel for drag. If it fits loose in the female end it will lose contact. Can the pcm be opened without destroying it? It may have cracked solder where it enters the box.

 

[ddgeramcharger79]

. Can the pcm be opened without destroying it? It may have cracked solder where it enters the box.

That's my big question.. I don't know if it can be opened up and fixed if the solder is broken loose cause I can handle fixing it.. if not then it means a new pcm

 

[ddgeramcharger79]

Alright guys.. fingers crossed..

I had the truck shut off on me several more times on the road and juggling the third plug on the pcm always got it going again... so I replaced the plug with a "new" one.. so far all is well.

I disconnected the computer completely and disassembled it and couldn't see any burns or broken solder points on the board so figured it had to be broken or loose connections in the plug.

 

[ddgeramcharger79]

Well after 2 major break downs in the middle of the road the conclusion is the pcm side of the ecu is bad. Once it gets hot it just shuts down. Have to wait for the thing to cool off and then tap on it for it to spring back to life. It's probably broken solder points inside but the computer is sealed in a gel