No crank/start no check engine light on

SARA PAYNE

MEMBER
2008 CHEVROLET COBALT
4 CYL
AUTOMATIC
84,000 MILES

Hello, I am so close to giving up. I got this car from a friend of mine. The mechanic said it was the ECU and had it replaced. When he went to the dealer they reprogrammed the new one and said it would not start because the battery was bad. My friend released the keys and it started and drove back home but once he shut it off it would not start again. Everything comes on like it is going to start. I got a new battery but it only clicks once when I try to start it. All lights come on except the check engine light. I hooked up a scanner thing from Wal-Mart(cheapo) and it says no communication with ECU/PCM but says compression good and N/A on almost everything else. I think it may have worked for a minute but my be touched the fuse box under the hood and it says lost communication now. The check engine light still never showed before but the OBD tool connected to it at least. Please what could it be? Also, the airbag symbol flashes a few times when I turn the key and power steering message displays. Sara

6 Replies

JACOBANDNICKOLAS

MECHANIC
108,320 POSTS

Hi and thanks for using 2CarPros.

If you are only getting one click when you try to start it, it sounds like a bad connection. Most commonly, the battery cables are to blame. They can be loose, corroded, the negative battery cable can be loose where it bolts to the engine block and so on.

With that being said and where the diagnose should start, take a look through these links. Follow the directions and let me know the results.

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

https://www.2carpros.com/articles/starter-not-working-repair

I will watch for your reply.

Take care,
Joe

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Thursday, November 22nd, 2018 AT 6:29 PM

SARA PAYNE

MEMBER
4 POSTS

Thanks so much. I will try this now. Would the battery cable problem cause the loss of communication and check engine light to not appear also? Or is that something else? I have not noticed a change in the lights dimming or anything when I turn the key.

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Saturday, November 24th, 2018 AT 1:12 PM

JACOBANDNICKOLAS

MECHANIC
108,320 POSTS

Welcome back:

Honestly, you would be amazed with what a bad ground can cause. Everything electrical on the vehicle needs a good ground. Since you are only getting a click, I have a feeling the ground is the problem or you have a bad starter.

However, if you find no problems with the ground or battery connections, I want you to check the starter itself. Here is a link that shows and explains how it is done. By doing this, we can determine if the problem is simply a bad starter.

https://www.2carpros.com/articles/starter-not-working-repair

The check engine light should turn on when you first turn the key to the on position and may shut off after a few seconds. If it does not, again, my first suspect is a bad ground. I can provide wiring schematics for the data link connector if you need them.

Let me know what you find. Again, make sure the ground wire to the engine block is clean, tight, and in good condition.

Take care,

Joe

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Saturday, November 24th, 2018 AT 3:34 PM

SARA PAYNE

MEMBER
4 POSTS

Okay. The battery connections are good and that big red fuse by it is not blown. The starter is new and the check engine light does not come on at all. Ever. I did get it to turn over by jumping the starter thing (I do not know the real term. Lol). The OBD scanner says code U1001 or something like that which is no communication with ECM/ PCM. The only other things it says is MIL on and compression good. All else is N/A.

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Sunday, November 25th, 2018 AT 11:58 AM

JACOBANDNICKOLAS

MECHANIC
108,320 POSTS

Welcome back:

Please confirm that it is a U1001. If it is, recheck all fuses in the under hood fuse box. If that is the code, there is an open circuit between the car's computers. It will not be easy to find.

Let me know,

Joe