engine replacement problems (U0100 code)

Tech discussions on the L77 6.0L V8.
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elmer91
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Joined: Sat Aug 15, 2015 6:00 pm

engine replacement problems (U0100 code)

Post by elmer91 »

I bought a 2012 roller that I put a mildly built motor into, also from a 2012. Got it all together, and it wouldnt start due to the ECM not matching the rest of the car. Had my brother use HP Tuners to turn off VATS. started no issues after that, just had a little pop up sometimes saying "engine immobilzed" due to the key code, BCM, and ECM not matching. Started it multiple times that night. Drove it home the next day without any issues. got it up to speed, no problems. Go to start it this weekend, and the gauges/radio come on, but it wont crank. Get the code U0100. My brother hooked up HP Tuners, and he couldnt even connect to the ECM.

I checked and cleaned all of the grounds i could find. The one on the drivers rear of the head, and the two that are together on the passenger head up front. Also took the fuse panel out, and the ECM out to make sure all of those connections were tight, and they seem tight to me. Is there anything else I could be missing? Does anyone have a pin out for the ECM?
2012 9C1 Caprice PPV, totaled
2012 9C1 Caprice PPV, soon to have TSP LS3 stage 1 cam, DOD delete, solo axle back, rotofab CAI, tuned
2005 Chevrolet Silverado 1500 Z71
1989 BMW 325i
smwalker
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Location: Azusa,CA

Re: engine replacement problems (U0100 code)

Post by smwalker »

Checked the ECM fuse correct?
Steve Walker
Azusa, CA
'11 PPV 9C3 Huron White
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Mooseman
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Re: engine replacement problems (U0100 code)

Post by Mooseman »

Yep, check fuse and if power is getting to PCM properly. You would need a schematic. Then I would bench test the PCM to see if it's still good. Either use the PCM connectors from the donor car or if you can get the pinout, hook it up to a power supply and HP tuner or a scanner just to see if it's still alive.
2011 Caprice PPV, former RCMP test vehicle, never put into service
Build Thread: http://www.newcaprice.com/forum/viewtopic.php?t=2419
elmer91
Posts: 37
Joined: Sat Aug 15, 2015 6:00 pm

Re: engine replacement problems (U0100 code)

Post by elmer91 »

All Fuses are good. First thing I checked. Steve Walker got me the pin outs for the ecm over Facebook last night. Going to start with that to see if power is getting to the ecm. If it is, then I'll power it up outside the car and hook up to it.
2012 9C1 Caprice PPV, totaled
2012 9C1 Caprice PPV, soon to have TSP LS3 stage 1 cam, DOD delete, solo axle back, rotofab CAI, tuned
2005 Chevrolet Silverado 1500 Z71
1989 BMW 325i
elmer91
Posts: 37
Joined: Sat Aug 15, 2015 6:00 pm

Re: engine replacement problems (U0100 code)

Post by elmer91 »

Here is a list of stuff I have tried so far

Checked Fuses and power at fuses, all good.
Checked connections to tranny and ecm, same conditions.
Unhooked battery for 1 hour, same conditions.
Check for burned or damaged wires around headers. No visibly damaged wires.
Checked for power at ecm. No power, if I am checking the right pins.

My guess is that maybe I have a bad wire that I can't see that is killing the power.
2012 9C1 Caprice PPV, totaled
2012 9C1 Caprice PPV, soon to have TSP LS3 stage 1 cam, DOD delete, solo axle back, rotofab CAI, tuned
2005 Chevrolet Silverado 1500 Z71
1989 BMW 325i
User avatar
Mooseman
Posts: 1075
Joined: Mon Jun 12, 2017 11:35 pm
Location: Ottawa, ON Canada
Contact:

Re: engine replacement problems (U0100 code)

Post by Mooseman »

I don't know about these cars but on GM trucks, ignition switches are failure prone and cause electrical gremlins when they do fail. That or a relay not sending the power to the PCM. Is there power at the fuses?
2011 Caprice PPV, former RCMP test vehicle, never put into service
Build Thread: http://www.newcaprice.com/forum/viewtopic.php?t=2419
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