Loose wiring maybe

2008 CHEVROLET COBALT
128,000 MILES • AUTOMATIC
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CHARLI ADAMS
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I leased a car through Carhop and it started having electrical issues, which were, not surprisingly, not covered by the warranty. It wasn't a big deal because it only happened once in a blue moon, but now it's happening quite a lot. When it happens, my dashboard turns into a haunted house, my gauges go absolutely nuts, I get fifty different warning messages popping up, I can't get a read on my coolant temperature, my power steering sometimes goes out, the A/C doesn't work, and the car lurches around every time it switches gears (automatically).
Aug 5, 2020 at 2:27 PM
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KASEKENNY
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This definitely sounds like a wiring issue. Possibly a loose ground wire. However, we need to get a little more to go on so can we check for codes and see if there is anything that points to a starting point.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Let's check for codes and go from there. Hopefully there is a fault against a specific component so that we can start testing some wiring and see if we can turn anything up.

Thanks
Aug 5, 2020 at 4:39 PM
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CHARLI ADAMS
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I ran the codes. There are so many, P0128, P0442, P0455, P0700, P2544, U0073, U0101, and U0100.
Sep 1, 2020 at 9:25 AM
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KASEKENNY
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Okay. That is good information. Clearly I am thinking we have a couple different issues because you have EVAP codes in there as well as transmission codes and sensor signal codes.

I attached the testing for the P0128 and P2544. I suspect if we go through these two codes and check for connection issues the we may fix the issues you are experiencing.

If you don't find anything, I would recommend replacing the TCM as it states in the P2544 at the end. Let me know what questions you have. Thanks
Sep 1, 2020 at 6:54 PM
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CHARLI ADAMS
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About ten minutes after I posted my reply, I pushed in some loose wires, cleared the engine codes, and so far, it seems like it's completely fixed. There's no check engine light, no more codes, everything is working fine.
Sep 1, 2020 at 7:04 PM
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KASEKENNY
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Haha. That is great. Thank you for the update. You have to love it when it is a free repair!

Thanks again and thanks for using 2CarPros.
Sep 1, 2020 at 7:35 PM
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CHARLI ADAMS
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Well, it's not fixed, replaced the coolant temperature sensor, but it's still throwing that code, plus the evap code, even though I replaced the gas cap, which makes me think it's the seat, not the cap. It's also occasionally throwing the throttle position sensor code. But if I keep the A/C on, it doesn't throw any codes. If I turn the heater on, it throws code and I can't get a read on the coolant temperature.
Sep 25, 2020 at 10:53 AM
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KASEKENNY
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Just to clarify, when you turn the heat on the ECT sensor reading goes blank?
Sep 26, 2020 at 6:40 PM
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CHARLI ADAMS
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Yes.
Sep 27, 2020 at 12:00 AM
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KASEKENNY
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Okay. So let's start from square one. Erase the codes and get it to act up again and let me know what codes return.

I suspect a lot of the issues are caused by the ECM not having the ECT reading but that is an electrical issue that could be causing 100% of it.

Let me know what codes come back and we can decide where to go.
Sep 27, 2020 at 10:02 AM
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CHARLI ADAMS
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The codes that pop are the evap and ECT codes.
Sep 27, 2020 at 10:04 AM
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KASEKENNY
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Okay. Can you list the specific codes just so we don't get it wrong? Thanks
Sep 27, 2020 at 10:09 AM
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CHARLI ADAMS
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P0128 and P0455.
Sep 27, 2020 at 10:31 AM
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KASEKENNY
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Okay. So we have to go through the P0128 testing again and solve this issue. Again, if we fix that code, I bet we fix most if not all the issues.
Sep 27, 2020 at 10:51 AM