its had new front air springs, front valve block, reservoir valve block and replacement compressor. Seems to come on at first start up - once the truck is warmed up it stays off.
Any ideas?
THX

 

Usually that code means the center block is not opening when the vehicle tries to fill the reservoir, therefore the pressure goes up way too fast.

 

so does that mean the valve block by the compressor needs replacing ?

 

You already replaced it, so I would say no unless you did not have that code before replacing it and replaced it with non OEM.

 

The one i replaced with was an Amazon “special” I still have the old original that I guess I could rebuild and throw back on

 

You can just install the old one loosely and see what happened. The center blocks rarely go bad.

 

Will do it tmrw afternoon. And report back

 

so. I put the original valve block back on. Threw the code immediately. Got another new one from Amazon. Put that on. Threw the code too. One interesting note. When I first put the new one on i didn’t mount it onto the chassis. Figured I’d test it wasn’t leaking first. Ran fine. Thought to myself. Hello. That must be it. Then I Mounted it. Buttoned up the plastic casing feeling pleased with myself and sure enough it threw the code as soon as I started it. Maybe I Shd just drive the thing with it hanging off under the car ? Any ideas ?

 

I would normally say the pressure sensor is then suspect, but valve blocks have the sensor therefore you have already swapped it a couple times. The ONLY thing that reads pressure is that sensor. I would observe pressure readings when operating and see what happens. Either you will get weird pressure readings, meaning the sensor wiring is bad, or the sensor readings will be fine and consistent with the error meaning you have a blockage, lines hooked up wrong or bad wiring to the center block that is causing the solenoid not to energize open. Dont forget, the center block has two connectors, one for the sensor and one to operate the center block.

 

Wondering if the wiring idea might be the case. It worked hanging and stopped installed. Perhaps a bad connection. Which connector is the offending sensor ? Rear of the vehicle side or front side ?