New Post 1999 Sierra 5.3 PIA

Taekdown918 · August 9, 2017

Hello All, I have posted in the past and I figured it is easier to post a new post with what U have done and it going on. I am still having the P0342 code popping up preventing me from getting my daughters truck emissions.

I have done the following:

-Replaced CanShaft Sensor OEM

-Replaced Crankshaft Sensor

-Jumped all thre wires back to the PCM (verified circuit)-New Battery

-New Cam Shaft Sensor Harness

-New Battery

-Triple checked wiring

Upon checking the wiring I got 12 volts, ground, low voltage ref and I do not throw a code if I start it and leave it in park. It does not even throw a pending code. As soon as I take it out of park it throws the P0342 code as pending. So I went and checked the wiring with it out of park and I get 12 volts, ground, and low voltage goes to zero out of park. So I went and disconnected the Park neutral switch on the transmission and wow the code went away even in gear. So I went and bought a new Park Switch and installed it. Plugged it back in and there is the code again. If I leave it unplugged it will not throw a code and runs great. So we were just going to leave it unplugged to get it through emissions. 6 days later we get a random P0341 code so I plug it back in and it goes away but the P0342 code came back on.

With the transmission switch unplugged it runs but throws a random P0341 code but with it plugged in it throws a P0342 every time it comes out of park. This thing is driving me nuts. I bought the All Data info on it and it says the plug on the transmission should all be 12 volts but when I test them I only get 5 volts. I am thinking the issue might be with a low voltage course somewhere but I have no clue a this point. I am at a loss.

Can someone please help me out with another thing to look at and get me started again. It is nuts that it will go away if I unplug the tranny sensor (only thought to do it since it only pops pending in gear including Neutral). I think the issue is something simple once I find it. Right now I have no clue where to go to next. We do not have the money to pay a dealer 600 dollars to diagnose it. Thank you for your patience.