I have been having an intermittent no bus problem. When this would happen the abs, brake, airbag, check engine light would all come on and all of the gauges die and no bus is displayed at the odometer. I have never been able to get a code to diagnose this. Well it happened again today so I checked and it threw a code this time p1687. Does that mean the cluster is bad or is it more likely the computer?

 

Have you tried removing the negative battery cable and cleaning the connections at the PCM?

 

I have replaced the terminals, cleaned and put dielectric grease on all connections I could find including three computer, I also made sure the ground for the computer was on bare metal.

After I did all that the problem hasn't happened for a few months so I thought I fixed it but it happened again today. Its raining today could that have anything to do with it?

 

Possibly. Have you done anything with the connectors at the back of the cluster?

 

Are all the gaskets to seal the hood when it's closed in place? Or is water dripping on the PCM?

 

I forgot about that. I pulled the cluster and cleaned and put dielectric grease on both of those connectors to.

One time when this was happening often I shut the truck off to go into a store. When I came back out the truck wouldn't start. I pulled the main fuse plug and put it back then did the same with the 3 computer plugs. After doing that it started but I still was having the no bus problem. That only happened one time and hasn't happened since.

 

The seal falls off part of the way all the time but Wouldn't it be hard for water to get to the pcm? It sits on the firewall and there is a lip sticking out where the seal goes. I guess water could be getting to it. Should I squirt it with wd40 or something? How do I fix that seal just glue it down with something like rubber cement?

 

Not saying it's getting into the PCM, just the connectors again.

 

Hmmmm I didn't consider the connectors getting wet again. I will have to check that once it stops raining.