Shut off while driving, engine cranks, but does not start?

Tiny
SHERLOCKTHC
  • MEMBER
  • 2007 CHEVROLET COBALT
  • 2.2L
  • 4 CYL
  • 2WD
  • MANUAL
  • 234,000 MILES
The coils and plugs and fuses are fine. I was driving, then the engine shut off. It will crank but no spark. I couldn't pop start it, but I saw the RPMs moving. I checked the fuses and tried a few tricks but no luck. After I had it towed, the tow driver left the lights on and ruined the brand-new battery. I charged it but my bidirectional scanner only reads a U2129-00 code now. I've had a lot of work done lately to pass inspections. I was trying to fix a P0171 code the day this happened. It was running fine; I took off the throttle body to check for leaks. I put it back on, drove only 3 blocks away and it shut off. The scanner seems to communicate with everything just fine. Upon inspection I discovered oil had leaked down the wire bundle into the ecu plug and elsewhere. I cleaned it all up but still no luck. The car is mechanically sound, I just put a ton of money into it. I've done some random troubleshooting but need help from square one. I'm worried it's a bad wire or connection somewhere but don't know what to check or where to start. Please help bring it back to life!
Monday, March 27th, 2023 AT 7:25 PM

15 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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If you had bad wiring, you would have a code for it most of the time, but I would start by checking the fuses to the PCM. Also, how does the engine sound when you are cranking it over? Can you upload a short video of the noise it is making so I can tell if it is in good shape?

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.
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Tuesday, March 28th, 2023 AT 8:44 AM
Tiny
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Would it still show a code for a wire if the battery has been disconnected?
The fuse seems fine. It communicates with my bidirectional scanner just fine also. But I did find oil in the connection. I cleaned and dried everything thoroughly and still no spark. The engine sounds fine while cranking. It was running perfectly before this happened. On the wires leading to coil 4, I found a short on the power wire. It rubbed against a bracket.
Would that stop the spark to all 4 plugs?
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Tuesday, March 28th, 2023 AT 5:09 PM
Tiny
KEN L
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Thanks for the video and the images, you can see the oil which could have gotten into the PCM which might make it malfunction. It would show a code but only if there was a code this kind of problem. You may have a bad PCM, you can get a preprogrammed unit by searching Google or Ebay. Check out the images (Below). Please let us know what happens.
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Thursday, March 30th, 2023 AT 12:46 PM
Tiny
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Is there any way to test this with my scanner? I have a Launch x431 v pro bidirectional scanner. The PCM seems to communicate just fine. I'm just trying to verify if ordering a PCM is the best option to try next.
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Friday, March 31st, 2023 AT 7:26 PM
Tiny
KEN L
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Not really, the scanner can command and monitor the PCM but not test it.
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Sunday, April 2nd, 2023 AT 9:46 AM
Tiny
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Well, I ordered a PCM from eBay. I'll reply here when I receive it. Is there anything else worth trying until it arrives?
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Sunday, April 2nd, 2023 AT 7:01 PM
Tiny
KEN L
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I would check the electrical connectors for corrosion, and I would check the power and ground connections and inputs.

Here is a guide to help and the engine and PCM wiring diagrams to help you with the test:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know what happens.

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Monday, April 3rd, 2023 AT 10:51 AM
Tiny
SHERLOCKTHC
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So, I got a P062F code with the new ECM. I can't get the new ECM to work. Any ideas on what could cause this?
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Wednesday, April 12th, 2023 AT 7:39 PM
Tiny
KEN L
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A P062F error in the EEPROM (Electrically Erasable Programmable Read-Only Memory). So it sounds like you got a defective or incorrectly programmed ECM.
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Thursday, April 13th, 2023 AT 11:55 AM
Tiny
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I tried 2 different ECMs. I'm confident it's not either of the ECMs. Could it be anything else?
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Thursday, April 13th, 2023 AT 12:22 PM
Tiny
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Also, I'm using a better multimeter now, (with the original ECM back in) I see a reading of 0.67v on pin D for the coil connectors. My previous multimeter didn't pick that up. I get the same reading using a power probe. Shouldn't pin D be 12v? The battery is reading 12v. What could cause the difference in voltage?
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Friday, April 14th, 2023 AT 4:28 PM
Tiny
KEN L
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The pink/white wire to the coil should be 12 volts. Try unplugging the coils to see if the voltage returns, you may have a shorted ignition coil.
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Saturday, April 15th, 2023 AT 10:10 AM
Tiny
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When I unplug each coil, the voltage goes up. When I unplug 3 coils it goes up to 2.8v. Any idea what could cause this and where to start? I found 1 melted wire, there was no improvement after I repaired it.
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Monday, April 17th, 2023 AT 6:39 PM
Tiny
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Any thoughts on my last reply?
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Thursday, April 20th, 2023 AT 6:51 AM
Tiny
KEN L
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If you unplug all of the coils does the voltage, go up to 12 volts? If so, you have a shorted coil. If not, I would test the power and ground inputs of the ECM using the wiring diagrams above.
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Friday, April 21st, 2023 AT 12:52 PM

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