I keep getting P0237 when I rev the engine quickly,  was lucky it did not do it for the Calif. smog check because it passed without throwing the code for him. I read that it is turbo boost sensor A circuit low.  would appreciate some info on this. why and what sensor is reading this. truck seems to run fine and boost will go from 0 to 28 psi. thanks.

in theory the edge should prevent that code from happening unless it is bad or you have a short between the edge and ecm.

Wiring issue, boost fooler issues, possible MAP sensor. Basically having a low volt issue. There is a margin on sensor voltage so if it drips to low or rises to high will trip a code. Boost coolers typical cover just high voltage. Edge comp I know you can unplug the MAP sensor and still not throw a code. 

 I struggled with this code and the engine running greatly defuled. While observing my scan gauge you could see and feel when signal dropped out. I am 99% sure mine is in the wiring harness near the ECM. I was able to grab the harness, move it some and squeezed it. The problem went away. Also had a surging issue that I dealt with in same manner. That issue started again 3 days ago. Performed the same grabbing of the harness and it quit. There is a ground splice in that location for most of the sensors and I believe that is my issue. You might give that a try and see if the code stays away after clearing it

 

I will check the grounds next. 

Body grounds are NOT sensor ground. Sensor ground are a floating ground created by the ECM.

The ground wire splice I spoke of are buried in the engine wiring harness. It is not like a ground to the body or such.

Edited May 23, 20186 yr by dripley

Here are a couple pics of the ground wire splices I am speaking. This first one is of the splice of the ground wires from sensors. This is similar to the ground splices described in @W-T's ground wire mod for the computers and I was thinking it could be the source of my issues. But maybe it's not. 

This second picture is another splice closer to the ECM. If I am reading the 02 wiring diagram correctly this splice is for the 5 volt supply to the MAP and the oil pressure sensor. It is also the area of the wiring harness I have been manipulating.

I did not pay much attention to this one when I opened up my spare wiring harness, it just caught my attention enough to take a picture of it.

 I don't know if either of these splices are your issue but it seems mine lays in there somewhere.

Does the ecm have to remain bolted to the motor or can it be relocated, and if we know where the ground originates from the ecm we can run a new one from there, can't we.  I do not talk from much knowledge of the wiring just of interest in making it better. thanks for informative pictures.

Edited May 24, 20186 yr by Ed ke6bnl

 I have read in thread or 2 where the ECM was relocated to the fender well. But it seems rare. I know nothing about how they did it nor do I really believe it would make much difference. But I like you cannot speak from any great electrical knowledge. I am a rookie with the electronics on vehicles. I am going to take a better look at that 5v splice when I get home this weekend. The picture asks more questions than it gives answers as to what all is in the splice.