Yes, you've totally got it. The problem is if the center block isn't able to vent the gallery stays charged so the pressure that is in the front and the rear is now connected together with the vent closed. The system doesn't care if it is Hitachi or an external compressor as long as the system reacts the way the computer thinks it should react (not too fast, not too slow, close the right circuit, etc). Often times replacing the block doesn't change anything if the contacts are still corroded.

 

That not accurate, the center block does not vent the gallery. Front and rear are always connected because there is no front and rear gallery, just one air gallery.

 

The front and rear vent through the center block. If the center block connects to the vent and the vent does NOT actuate the lines are then connected and the pressure equalizes in the full system. I realize lumping the systems into one is a simplistic way of looking at it but the reality is it isn't as complex as It is made out to be: The Front line is highlighted in teal, the rear in purple, and the air supply / vent is in red. The point is, I've seen people replace entire systems when simply cleaning the contacts would have corrected 90% of their problems:

 

There is nothing in the center valve block that "vents" or controls venting itself though. There is one valve in the center block for the reservoir and it only opens/closes the line to the reservoir. At the center block all the other lines are part of the gallery, which is one plenum of air, monitored by the pressure sensor. The air lines to the front and rear blocks are always open to eachother along with the line to the compressor, hence why its called the air gallery. If it were not for the reservoir or pressure sensor, there would be no center block.

 

I will try the electric goo on the pressure sensors again, but is there any reason that it could be the reservoir or the Voss fitting clogged going into the reservoir. The fault says increases too quick but idk. I’m at a loss. Got a long trip coming up. If the fault isn’t serious I’ll just leave it. But I’d hate to have to try a repair on the road. Any new ideas, suggestions?

 

Recap time - electric goo? If its contact enhancer, fine. But if its dielectric, never a good idea ever to apply it to the mating surfaces of the conducting pins. I mean it is di-electric after all. And when it comes to sensors that generally operate on resistance values, that grease has been proven to cause issues when not used properly.

You can always remove the fittings to see what happens. Be advised there is a ton of air so do so with care. But a clogged line would not be common, people always say it could be but I have yet to see a line that was actually clogged. Also as I mentioned before, if not a genuine pump then it could be the issue too.

 

yes I meant di electric. Several people said that would be good. I will scratch that and try contact enhancer. Also yes I hooked up my old pump which was genuine, and I got the same code.

 

So I just replaced my reservoir and Voss fitting. I cleaned the central block contacts really well… still getting the same code. I will try and reset the whole computer and clean the front and rear pressure sensors as well. I’m just at a loss. It’s seems to work fine but bothers me with faults flashing. The above remedies are long shots; any other ideas would be welcomed! One thing I will add and who knows if it’s relevant is that it is throwing one other code b1c57-14. Maybe the whole issue is electrical? I’ll attach the two codes for reference… maybe one has something to do with the other?

 

Maybe it’s the crappy relay they gave to me? When I got the air compressor they said I had to use their relay? Any thoughts on that?

I tried resetting the comp, and nothing. Every time I start the truck I also get these codes. They go away when I clear them but maybe useful to someone helping me figure this out.


also I should add that it only happens under 30degrees and over 80 degrees… seems electrical but idk. I wish I could pretend it’s not there, but I don’t like giving up and settling

 

Maybe your center valve block solenoid is not opening when energized. Which would mean a faulty center valve block or wiring.