No Crank After Replacing Ignition Switch

[PyroGuy923]

Recently the car started to stall when running and occassionally wouldn't start. After doing some digging there was an igition switch recal on the Cobalts. I order a new switch with the intention to swap it out and learn the new key but boy was I wrong. I swapped the ignition switch and the car won't crank even after going through the relearn process multiple times (On 10 minutes, off 30 seconds, repeat 3 times). There is no security lock on the gauge cluster which is odd.

Thoughts? Checked numerous fuses at the BCM and engine fust panel. Fuel gauge isn't registering, no oil life, coolant temp showing -40 F.

https://static.nhtsa.gov/odi/rcl/2014/RCRIT-14V047-5733.pdf

 

[MJP61]

Typically if the coolant temp shows -40, it means the coolant temp sensor is unplugged or no good. Not sure if that would cause no crank though.

 

[Ark :D]

Coolant temp -40 also means no data communication between the BCM and ECM.

• Re-seat your BCM and ECM plugs, applying lots of pressure while you flip the levers
• Check the 50-amp fuse near your battery

 

[Rttoys]

With multiple things not working or just off, I’d look into a wiring problem like a loose ground.

 

[ctuinstra]

The recall was for a small pin and spring that held the key in the on position. When certain people like to carry 10lbs of personal belongings and momentos on their key rings, the weight tends to shut off the ignition when you hit a bump.

Either way, I can't help to think you have more going on than the key switch issue. Can you change it back out to get back to the point of the car starting again? All you really have to do it move over the harness to the original one while you give it a try. What exactly did you change out? There is a very specific value resistor in the bottom of the key unit. I doubt that is causing a problem bet I have noticed that not all are the same value.

 

[PyroGuy923]

The recall was for a small pin and spring that held the key in the on position. When certain people like to carry 10lbs of personal belongings and momentos on their key rings, the weight tends to shut off the ignition when you hit a bump.

Either way, I can't help to think you have more going on than the key switch issue. Can you change it back out to get back to the point of the car starting again? All you really have to do it move over the harness to the original one while you give it a try. What exactly did you change out? There is a very specific value resistor in the bottom of the key unit. I doubt that is causing a problem bet I have noticed that not all are the same value.

Going back to the old switch doesn't work unfortunately. It was the ignition switch on the back of the key tumbler.

I'll check the 50 amp by the battery.

I can't imagine it being a ground as it ran for months before changing out the switch. Sometimes I would run it for 45 minutes at a time. It recently got a brand new battery but ran fine after that.

When keyed on the fuel pump, heat exchanger fan, horn, and all the lights work.

 

[ctuinstra]

So you changed out this, or the whole assembly?

Inside that black unit, is this circuit board with this theft deterrent resistor on it. Again, I'm not going so far to say this is your problem, but something to keep in the back of your mind before you go crazy over it. There has been some question on the value of the resistor. The diagram says 1.3K while I measured 1.8K on mine. It may not even make a difference, but I can't help but to wonder if it worked before and doesn't work now.

 

[PyroGuy923]

So you changed out this, or the whole assembly?

View attachment 22275

Inside that black unit, is this circuit board with this theft deterrent resistor on it. Again, I'm not going so far to say this is your problem, but something to keep in the back of your mind before you go crazy over it. There has been some question on the value of the resistor. The diagram says 1.3K while I measured 1.8K on mine. It may not even make a difference, but I can't help but to wonder if it worked before and doesn't work now.
View attachment 22274

Yeah, that black electronic piece is what I swapped out.

 

[Rttoys]

Do you have hp turners? Just turn off vats and see what happens.

 

[ctuinstra]

Yeah, that black electronic piece is what I swapped out.

Just so I understand completely, you changed out just the black piece and not the key assembly? If this is the case, you don't need to do a key relearn. You should still be able to use your original key in the original lock. And if you changed out only this unit, then the issue must be with this unit.

 

[PyroGuy923]

Do you have hp turners? Just turn off vats and see what happens.

I don't.

Just so I understand completely, you changed out just the black piece and not the key assembly? If this is the case, you don't need to do a key relearn. You should still be able to use your original key in the original lock. And if you changed out only this unit, then the issue must be with this unit.

I did just replace the black unit and not the whole assembly. What has me baffled is when I change back to the old unit it doesn't crank anymore.

 

[ctuinstra]

Okay. I'm following you now. I misunderstood some of your comments. I'm agreeing with some of the others, you have a communication issue. If you are not getting the correct temps, fuel, and oil info, there is a lack of communication and it's never going to give a request to crank.

I wonder about reseating the fuse box as others have had issues with that. Sounds like a poor connection somewhere and it's finally got bad enough to not work at all.

 

[Ark :D]

Especially make sure you've drawn all of the 7mm bolts in the engine fuse box, very tight.

 

[PyroGuy923]

So found out the ignition switch wasn't the issue, just a really strong coincidence.

The 50 amp fuse by the battery is good. All the connections at the BCM are good as well.

The 7mm bolts in the fuse box don't get tight, none of them.

We were get it running for short periods by either pressing on the larger ECM connector (the untouched one closer to the engine) or slightly moving wires. On the contrary we couldn't get it to cut out doing either of these with the plug.

No other engine codes other than 2 EVAP system ones. I did see once it showed Reduced Engine Power, sputtered, then started idling properly again.

Wondering if the crank position sensor is going bad? But its not throwing codes.

Theories and how to possibly test them?

 

[ctuinstra]

You said that none of the bolts in the fusebox ever get tight? It's not seated all the way down. Everyone who has ever said that found out later that they could get them tightened and usually took care of their issue.

Press down firmly all around the fuse box. Put a 7mm socket on the bolt and a short extension. Now politely hammer down each bolt and then see if they tighten. Don't break things, but the bolts pull all of the connectors together. This is very important.

 

[Ark :D]

So ALL your fuse box connectors are stripped out? Wow. I'd maybe remedy that with a small amount of that puffy spray insulation stuff under your fuse box connectors, at some point. Or something else easily removable. You don't want any of those working loose while you're driving.

No idea on the crank shaft position sensor, though.

 

[PyroGuy923]

I wasn't able to push down on the 7mm bolts and get them to tighten. I split the fuse box apart about 2 inches and was able to push up on the connector and get all but 2 bolts to tighten down.

Car fired right up after that but stalled after about 30 seconds. That happened probably 5-7 times before finally running for over 10 minutes before it stalled out again.

Beginning to think I have sensor going bad or worse, the ECM.

 

[Ark :D]

You said that none of the bolts in the fusebox ever get tight? It's not seated all the way down. Everyone who has ever said that found out later that they could get them tightened and usually took care of their issue.

Press down firmly all around the fuse box. Put a 7mm socket on the bolt and an short extension. Now politely hammer down each bolt and then see if they tighten. Don't break things, but the bolts pull all of the connectors together. This is very important.

You're making progress, but as Chad said above, you MUST get those bolts tightened down. Why can't you, exactly?

 

[ctuinstra]

I doubt it's the ECM. Usually if they are going to fail, it's only part of it and it would fail hard and consistent. Do you get any new codes? Can you clear your old codes and read any new ones. I almost wonder if you are having a fuel pump issue or something like that if it does run and then dies. We had problems with our fuel pump not wanting to prime, replaced it and the new fuel pump failed after one year.

 

[PyroGuy923]

You're making progress, but as Chad said above, you MUST get those bolts tightened down. Why can't you, exactly?

They just spin. I can’t tell if they just aren’t engaging or are stripped. Due to wire routing I can’t get the upper separated more than 2 inches from where the connectors are.

I doubt it's the ECM. Usually if they are going to fail, it's only part of it and it would fail hard and consistent. Do you get any new codes? Can you clear your old codes and read any new ones. I almost wonder if you are having a fuel pump issue or something like that if it does run and then dies. We had problems with our fuel pump not wanting to prime, replaced it and the new fuel pump failed after one year.

Fuel pump primes. It ran for roughly 2 hours this weekend when trying to do the key relearn cycles. Would a bad fuel pump cause it to not crank over? Like no audible sounds when trying to start.