Ignition 1 Signal 0 volts Engine turns over but wont start! - SOLVED

[BPiatchek]

I have a 2004 Chevy Tahoe. I’ve been having problems off and on with it not starting. Engine will turn over, but will not start. Well, its gone from intermittent to now it wont start period.

I attributed this to a PASSLOCK issue since my code scanner was showing VTD Fuel Disable Active. I had changed out the ignition a few weeks prior. So I sent the ECU out to have PASSLOCk removed. Got it back today, still not starting. Now the VTD fuel disable is not active anymore, but I am still showing “ ignition 1 signal 0 volts.” I suppose this means I have a whole separate issue..

Again, the engine will turn over but will not start. I thought maybe the neutral safety switch might be the culprit. I shifted to neutral and tried putting pressure towards park while starting. That didnt work. I suppose I need to actually find where that switch is so i can test it with a meter. I pulled every fuse and checked in both the engine bay and the cabin drivers side fuse box. I checked in the engine bay fuse box B+ to both sides of the ECU fuse. I had 12V on one side..

Does anyone have access to whatever circuit this ignition 1 signal is reffering to? If I could at least know whats on that circuit, I can start at the ignition switch and work my way back to the ECU. Any other ideas guys!

Thanks so much for your time!

 

[S33k3r]

I do not have a wiring diagram, but I can share an experience that might help:

Our issue was that multiple electronics were out, but not all of them. It would start and run, but the dash was pretty much disabled. This got traced to wires having gone bad just before the ECU. So if you don't get a wiring diagram, you might just check those wires.

 

[Scottydoggs]

have you checked for fuel at the rail key to run yet?

does the tach move when cranking it? if not crank sensor might be bad.

 

[Donal]

I have a 2004 Chevy Tahoe. I’ve been having problems off and on with it not starting. Engine will turn over, but will not start. Well, its gone from intermittent to now it wont start period.

I attributed this to a PASSLOCK issue since my code scanner was showing VTD Fuel Disable Active. I had changed out the ignition a few weeks prior. So I sent the ECU out to have PASSLOCk removed. Got it back today, still not starting. Now the VTD fuel disable is not active anymore, but I am still showing “ ignition 1 signal 0 volts.” I suppose this means I have a whole separate issue..

Again, the engine will turn over but will not start. I thought maybe the neutral safety switch might be the culprit. I shifted to neutral and tried putting pressure towards park while starting. That didnt work. I suppose I need to actually find where that switch is so i can test it with a meter. I pulled every fuse and checked in both the engine bay and the cabin drivers side fuse box. I checked in the engine bay fuse box B+ to both sides of the ECU fuse. I had 12V on one side..

Does anyone have access to whatever circuit this ignition 1 signal is reffering to? If I could at least know whats on that circuit, I can start at the ignition switch and work my way back to the ECU. Any other ideas guys!

Thanks so much for your time!

You said, "I had changed out the ignition a few weeks prior." Exactly what was replaced? What about the fuse where you had 12v on one side?

 

[BPiatchek]

Scottydoggs, My tach needle barely moves, but it moves when cranking. So, I hooked up my scanner to watch the live engine data "engine speed" RPM - When the engine begins to turn over RPM reading jumps from 0 to about 155. I don't know if it's normal, but after the engine stops turning over and key rocked back, the engine speed readings remianns at 155..

 

[Scottydoggs]

Scottydoggs, My tach needle barely moves, but it moves when cranking. So, I hooked up my scanner to watch the live engine data "engine speed" RPM - When the engine begins to turn over RPM reading jumps from 0 to about 155. I don't know if it's normal, but after the engine stops turning over and key rocked back, the engine speed readings remianns at 155..

ive never watched on my scanner, so im with you, not sure if thats normal. id think it should drop back to zero again.

 

[BPiatchek]

Donal, I changed out the "ignition switch w/ assembly"



I had to replace the ignition switch because it had become rusted \ corroded on the inside. I had problems with the PASSLOCK ever since. I kept having to do that process where you leave the key in the ON position for 10 min intervals. Then it began to intermittently not start. What I mean is, I would turn the ignition, wouldn't start. I'd turn off the ignition for 20 secs, try again. Repeat a few times, eventually it would start. Every time though, the engine would turn over.... Which leads me to believe perhaps I never had a PASSLOK issue. Maybe it was this Ignition 1 signal circuit all along. I saw this on my reader highlighted in RED. I just assumed it was related to PASSLOK.

Not only did I visually check that fuse, I checked it with my meter

 

[Fless]

The owner's manual could be helpful; if you don't have one, download it here:

Site Maintenance

or https://www.chevrolet.com/support/vehicle/manuals-guides

I've indicated a few of the IGN fuses and relays, so you may want to start checking them for pin fitment and blown or defective fuses.

Instrument Panel Fuse Block (left side of the instrument panel; open the driver's door and pull the cover off):



Underhood fuse block:



That might not even be all of them, but gives you a place to start. Use a voltmeter to test the mini fuses using the integrated test points, but also pull the fuses to verify the legs are intact and fit tight into the connections.

 

[S33k3r]

It occurs to me that you might have a faulty replacement. May I ask what brand you bought?

 

[BPiatchek]

Fless - That's awesome! All good information. I am going to dig into those fuse panels when I get home this afternoon. Although I have visually checked all of those fuses, I haven't checked all of them with my meter. So that would be good to do. I have had fuses that looked good and tested bad before.

One question I had for you. I suspect it's entirely possible I may have a defective fuse panel. I would think the way to test this would be to check from b+ to the fuse posts to make sure I am getting voltage to the fuses themselves. In my profession ( Automation Controls ) I work a lot with low volt electrical. In my mind, I should only have power to one side of every fuse. that being said, I ran across a few posts saying to check and make sure I had voltage to BOTH fuse posts on certain fuses. I think it was the ECU fuse I was supposed to have voltage to BOTH sides of the fuse. This dosen't make any sense to me, but I saw this on more than one post. Another thing, i was expecting to read 12V POSITIVE to each fuse post getting perhaps a common or negative from the body / ground and positive 12VDC at the fuse post. I suppose this is wrong, they run common through all the fuses. This is why you grab positive from B+ and test with your common lead from the meter to each fuse post.. Maybe I am misunderstanding what they are saying about having 12V on both fuse posts for the ECU fuse.. How should I properly be testing these fuses? Which fuses should have power on both posts from B+?

The second thing I was going to try - I going was to take apart the steering column cover to expose the ignition switch and try to follow the pink wire coming off my ignition switch (I believe the pink wire is the "Ignition 1 signal circuit." Which is what my code scanner is reading 0 volts back to the ECU. I am still going to have to try and find a wiring diagram for this circuit so I can follow it. It's either that or try to physically trace \ follow the wire, which I really don't want to do. I don't know why it has been so difficult to find this wiring diagram for the ignition 1 signal circuit!

Thanks for the owner's manual. If you can believe it, I have the original in the glove box, although I don't believe there is anything in there that's going to help me...

The owner's manual could be helpful; if you don't have one, download it here:

Site Maintenance

or https://www.chevrolet.com/support/vehicle/manuals-guides

I've indicated a few of the IGN fuses and relays, so you may want to start checking them for pin fitment and blown or defective fuses.

Instrument Panel Fuse Block (left side of the instrument panel; open the driver's door and pull the cover off):

View attachment 431605

Underhood fuse block:

View attachment 431606

That might not even be all of them, but gives you a place to start. Use a voltmeter to test the mini fuses using the integrated test points, but also pull the fuses to verify the legs are intact and fit tight into the connections.

View attachment 431610