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2010 Chevrolet impala LT flex fuel 3.5l v6

1108 Views 25 Replies 5 Participants Last post by  Impoor
I have a 2010 Chevrolet impala lt flex fuel 3.5 v6. I have been without a car since October. First my car started going into limp mode, it would stay running but when I hit the gas nothing happened. I took it to 2 parts houses and they both told me something different. I borrowed a obd2 scanner and every time it would give me a code and I would change said part, another code would come up days later and it still drove the same (limp mode) or rpms higher than normal. Since October, I have changed Map sensor, MAF sensor, camshaft sensor, wiring harness for the camshaft sensor, oil pressure sensor, VVT solenoid, changed the oil and filter, ect. It has always cranked and ran fine until recently and it wouldn't start, even though it has good power. Now its giving me a code (U0100) Lost communication with ecm/pcm "A" ..
I'm not sure what the A is but I did have a code that came back camshaft position sensor open circuit "A" which I changed the sensor and harness. I dont know if I need a Ecm/pcm or a TCU since they both run hand in hand. I truly appreciate any advice or recommendations you can give me. I have done all the work myself with the help of a obd2 scanner and Google. I'm out of options here. Does anyone have a wiring diagram for circuit "A" please.
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6 to 14 I got 62.0 ohms and .03v
6 to 16 It either went blank on the meeter or 1 time I got it to read 88 to 103 ohms jumping back and fourth, and 11.36 volts
6 to 16 was. 33 ohms and 0.02 volts
6 to grond was 1.00 volts
14 to ground was 1.00 volts
You need a wiring diagram. You need to make sure you have all the power and grounds to your ECM. Also, in order to check the data lines, CAN bus, you need a lab scope. This is where you need to find a technician, not a parts changer, that understands how the data flows in these new systems. Only when you see what the data lines look like, can you go forward to determine which module is causing the problem. You could also have a shorted sensor pulling the data lines down as well. This is where a scope is invaluable in troubleshooting communication issues today.
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I'm hoping Chevrolet or gm will email me back with that information. I have tried to find a mechanic around me, I thought I found 1 and he said since I didnt have a code visible that he couldn't do the computer part of the car and just told me what the outside needed, and still charges me $100. I deleted the camshaft sensor code after I replaced it and the harness, hoping that was gonna fix it. So since he didng see that code then, he said he couldn't pull codes with his computer. Hopefully I'll get this diagram soon and go from there. Or find someone that knows what there doing that can come to my house.
There are stored codes that a good quality scope can pull up providing they haven't been erased previously. A savvy technician should know that. I would reach out to the Scanner Danner website. You can join and present your issues on the website. There are some really good technicians that prescribe to the website that can help guide you along. Sounds like you either have a module that is dead or a sensor shorting the data line. CAN buss. You can take a multimeter and check the 5 vdc at all the sensor connectors. They should all have a 5 vdc. If not, the sensor is shorted. Disconnect the connector. If the 5 vdc returns, you have identified the problem sensor. Another way is to disconnect every sensor and see if the problem disappears. That will tell you if you have a bad sensor. Thats a lot of work but may be the best route. If all the sensors are good, then its either a bad module or a shorted wire somewhere. Also, as has been mentioned, be sure every connector to all the modules, especially the ABS/Antilock brake module is completely connected. That connector has to be completely seated. If it isn't, it can cause some weird issues.
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