# No crank and U0100 Lost Communication With ECM



## FireFox31 (Mar 28, 2018)

My 2012 1.4 LT won't start because the car has lost communication with the ECM. How can I test the connections to the ECM? How can I test if the ECM is working or dead?

Connecting an OBD-II scanner gives the code U0100 Lost Communication With ECM/PCM "A". Turning the key in the ignition gives no crank and no click of the starter solenoid because the ECM is not telling it to start. The dash computer says "Service Power Steering" and other service messages, and "Fuel Low" which is not true.

I had the original bad negative battery cable when this problem started. I replaced it with the new cable but that didn't fix the problem.

Please let me know any ideas for checking communication to the ECM and testing the ECM to see if it's working. Thanks.


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## Thebigzeus (Dec 2, 2018)

I thought you mentioned in your other thread you took this to the dealer? What did they end up saying?


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## FireFox31 (Mar 28, 2018)

I posted the outcome to the other no crank thread. Sorry for starting a second thread. I was worried the dealership wouldn't find the problem, so wanted to ask the pros for input.

All the trouble was caused by a mouse chewing through some wires under the battery and fuse box.


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## RoninDusette (Aug 21, 2018)

I was just going to say to check the fuse box under the hood. Mine has rattled itself loose twice. Bolted it back down after inspecting for damage and everything went back to normal. Glad you found the solution.


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## Chicker3 (May 29, 2021)

FireFox31 said:


> My 2012 1.4 LT won't start because the car has lost communication with the ECM. How can I test the connections to the ECM? How can I test if the ECM is working or dead?
> 
> Connecting an OBD-II scanner gives the code U0100 Lost Communication With ECM/PCM "A". Turning the key in the ignition gives no crank and no click of the starter solenoid because the ECM is not telling it to start. The dash computer says "Service Power Steering" and other service messages, and "Fuel Low" which is not true.
> 
> ...


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## Chicker3 (May 29, 2021)

Please tell me you figured out how to fix it? My 2013 Chevy Cruze LS 1.8L is doing this too after putting a new PCM in it


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## Jesus j castillo (Jul 9, 2021)

Chicker3 said:


> Please tell me you figured out how to fix it? My 2013 Chevy Cruze LS 1.8L is doing this too after putting a new PCM in it


Have hood and doors close but recomend to put battery charger in charging mode of 2 amps slow charge you can be inside or out of the car if want to put your key on the ignition switch. Then open the key to start mode dont start the car just on start mode let it for 10 minutes and came back am close the key on off position for 1 minute whit out taking the key off and after the minuter turn key back on start mode position and after another 10 minutes came back and turn your key off for other 1 minute after minute for third time came and put your key on start mode again let it for the last 10 minutes after that turn back off the key to off position again whit out taking key out of switch never take it out after the minute open key for 5 seconds on start mode and now start the car on it will be program new pcm and read all control modules on car and ready set on pcm.


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## Gzuz4132 (Jul 13, 2021)

@Chicker3


Chicker3 said:


> Please tell me you figured out how to fix it? My 2013 Chevy Cruze LS 1.8L is doing this too after putting a new PCM in it





Jesus j castillo said:


> Have no load on the car. No lights, radio, close the hood and doors, etc. I recomend also using a battery charger at 2 amps slow charge. (*Please follow instructions on how to charge a battery while installed in the car*)
> You can be inside or outside of the car (with the window down). Put your key in the ignition.
> Turn the key to the start (*RUN??*) position but don't start the car just turn it to the start (*RUN??*) position for 10 minutes
> After 10 minutes turn the key to the off position for 1 minute but do not remove the key
> ...


Not verifying this is valid!
it just made my hair hurt trying to read it so I edited for readability


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## Mrdee863 (Mar 29, 2021)

Does anybody know anything about why my bcm will not accept programming ? I’ve tried 3 different ones an still nothing


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