4l80e swap issues no crank
07-08-2013, 01:59 PM
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4l80e swap issues no crank
Did a 4l80e swap in my 03 silverado with a segment swap and removing the white wire and replacing with the brown wire. Used 2 wires from the unused rear o2 sensors for the VSS and swapped them at the PCM to the 22 23. I have tested everything I can think of pulled the whole trans wiring harness out from the hood striped it and found no broken wires. Tested continuity between all the wires to the trans, nns and PCM and ground. Replaced and played with the neutral safety switch. Replaced the internal trans harness. The issue is that the PCM thinks the trans is in 2nd gear. Well that is at least what my hp tuners is telling me. I have voltage from the crank fuse to the PCM on the purple wire but no voltage from the PCM to the starter relay on the yellow / black wire. On the nns the big plug seams fine but the smaller one on the yellow wire I have 10v in park. Anybody have any ideas of what else it could be? My next test will be replacing the pressure switch inside the trans.
Last edited by kent91011; 07-09-2013 at 09:20 AM.
07-08-2013, 03:09 PM
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Did you cut any wires on the neutral switch? If its saying its in 2nd its won't start must be in park or neutral to start...your best bet is go through the wires and area of wire you was messing with trouble shoot from there....if everything seems good to you then mist in the tranny tune
07-09-2013, 07:45 AM
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After testing the pressure switch got me no where. Slowec is going to gather me up some schematics and ill do some more testing. Anybody else have any ideas??
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07-09-2013, 11:34 AM
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Make sure all your wires in the p/n connector are fully seated.. Dropped a tranny out of a truck once, as we were lowering it down the connector caught on the trans and it pulled a few wires out of the connector and it was doing the same thing your talking about.. It was about 5 in the morning once we figured out there was a few wires pulled out in the connector.