So I had a bunch of codes on the truck, new map sensor took care of the p0237, but I still ended up with p0238 code for over boost. The problem is, I can't even clear the code and the truck is obviously in some sort of limp mode. I can erase the code, but it instantly comes back.

I've pulled batteries, then reconnected, tried erasing codes with code reader, have done the turn on and off three times, then erase codes.

The ground works on the map sensor, the positive puts out 4.8v, the grey sensor wire puts out 4.8v not running but on. I've been searching the freaking google, this site, among others for days if not a full week. I've seen people figure out a fuel issue, map sensor, damaged booster circuit right in the ecm (how do I test for this?)... someone putting the ecm power directly to the battery to solve the not seeing the map sensor properly. Just need a little direction.

I figure tomorrow, pull ecm, make sure that grey wire is plugging into it correctly. I have this feeling its a wiring issue, but have pulled and reconnected every connector I could find. Everything looks good now.

Have also reset apps, which took care of that error code.

 

Also if I pull map sensor, I get my p0237 code back. Hadn't tried resetting it that way yet. Will try tomorrow.

 

My only suggestion I can make
Is mopar1973man.com or bluechipdiesel.com these two pages are great if you haven't gone there good luck please keep us posted

 

I dont see a signature for your truck so I dont have much to go by. So, do you have any electronic performance boxes on your truck? If so, unplug/remove everything and see what that does.

 

Trucks stock with 4" exhaust and cai.

Worked through most of mopar, my scan tool isn't reading map sensor or doesn't have the option, thought there was no continuity between ecm and map, but there might have been, just female pin was further in the connector. Had redone the wire from map to ecm anyways. All the others checked out. Pretty much, just need scanner which will be tonight at a buds. Thinking ecm needs to be reflashed. :-(

 

Although after putting fuel gauge in, seems my lift pump is on it's way out, works intermittently. And maxes at 3 psi. Awesome.

That wouldn't cause the map sensor issue though?

 

Have you checked your lift pump flow volume with the key bump?
Just to eliminate one more thing,if you pull you fuel line loose at the inj pump and bump your key it should run for 20 seconds and pump about 1/2 gal

 

A scanner should recognize the MAP sensor. Unplug the MAP and see if it throws a code.

 

Ya flow isn't good at all. Have new lift pump coming tomorrow. Pulling map sensor sets code 0237 which is map sensor low voltage.

reflashing truck friday, seems all wiring is good and it's possibly a ecm issue.

 

I've seen codes set because of poor connection at ECM I had to replace wire connector because Customer used test light to probe connector spreading the connector.

 

Ah that's not good. Still flash, if that doesn't fix, will jam some fine copper in that pin.