engine not cranking over?

2004 GMC YUKON
175,000 MILES • 5.3L • V8 • 2WD • AUTOMATIC
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HAILEEGRACE12
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I was waiting for my wife to come out of the store and parked in the shade on a pretty steep incline facing downhill and accidentally fell asleep when she came out and woke me, I panicked and immediately shut the car off. Well, it would not start back and was starting to overheat so from where I tried to start it back, it just went further and further down this incline until I was stuck. Couldn't go anywhere. So, when I tried starting it again. It was only cranking would fire up . I checked the Shrader valve on the fuel rail and nothing was coming out. But I could hear my pump running. So I thought maybe it didn't have enough fuel. Went and got fuel ,I thought maybe it was the ignition switch, but I replaced it and didn't fix it.
put it in, and now it's not even cranking. I tried to just bypass the starter solenoid just to get it home and I could get it to crank that way but will not start up. Oh, and the fuel is gushing out at the rails now so that problem is fixed. Why won't it start up ? I've been stuck here for 5 days now. Maybe the neutral safety switch? I just don't have any experience with those. Please help.
Jun 25, 2024 at 9:14 AM
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HAILEEGRACE12
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Also, I cannot figure out where this wire goes under by steering column!!
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Jun 25, 2024 at 9:33 AM
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STRAILER
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The first thing I would do is lift the hood and check the fuses in the PDC (key on). Here is a guide to help you. Also try cranking the engine over in neutral, this can help test the gear range sensor, (neutral safety switch):

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

Also please go over this guide can well:

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

Here are the fuse locations which you should check fuses: IGN a, IGN b, IGN e, and the crank fuse. There is also a starter relay you can try swapping out. I have also included the starter motor wiring diagrams so you can see how the system works. Check out the images (below). Please upload pictures or videos in your response to any problems so we can see what to help you with.



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Jun 25, 2024 at 11:55 AM
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HAILEEGRACE12
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Okay, sorry for the late reply but I am still stuck on this. I have tried everything I can possibly think of the only logical explanation I can come up with is the security system is keeping it from cranking. I can pull the relay to the starter and jump it with a wire, and it will crank all day but won't start up. But it will not crank at the ignition. It's getting fuel to the rail I've checked every fuse and relay, I've checked that everything is getting voltage it should I've changed the neutral safety switch the ignition switch, the ignition cylinder and key, I've tried to relearn the key with no success, and when I hook a code reader to it, any code reader, it just says error. Please help me here I'm going insane!!
Jul 8, 2024 at 5:57 AM
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STRAILER
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Lets try resetting the alarm system.

Alarm Reset: Try resetting the alarm system. This can often be done by locking and unlocking the doors with the key or the key fob.

Passlock Relearn Procedure:

Turn the key to the "ON" position (don't start the engine).
Leave the key in the "ON" position for about 10 minutes until the security light stops flashing.
Turn the key to the "OFF" position and wait for a few seconds.
Repeat this process two more times (for a total of three cycles).
After the third cycle, turn the key to the "OFF" position, wait a few seconds, and then try starting the engine.

Please let us know what happens.
Jul 8, 2024 at 10:33 AM
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HAILEEGRACE12
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I did it and it stopped flashing but now it's just on continuously without the flashing. Everything else is just the same. Resetting the alarm didn't do anything either. Whoever had the truck before me took out the entire center console and I remember when I first got it, it would stall out if I hit those wires wrong and wouldn't start back. I have checked every one of them already to make sure no bare wire showing, and all are getting the voltage there are supposed to get and they all check out. Don't know if that helps.
Jul 8, 2024 at 2:59 PM
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HAILEEGRACE12
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I did it and it stopped flashing but now it's just on continuously without the flashing Everything else is just the same. Resetting the alarm didn't do anything either. Whoever had the truck before me took out the entire center console and I remember when I first got it, it would stall out if I hit those wires wrong and wouldn't start back. I have checked every one of them already to make sure no bare wire showing and all are getting the voltage the are suppose to get and they all check out Don't know if that helps
Jul 8, 2024 at 2:59 PM
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Okay, do you have power at the IGN A, IGN E, IGN B and the crank fuse when the key is in the crank position? This guide can help us test them for power. Also, let's try swapping the starter relay out as well to see if anything changes.

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

Please go over this guide and get back to us.



Jul 9, 2024 at 9:33 AM
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HAILEEGRACE12
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I have power at all the fuses you listed also swapped the starter relay, no changes.
Jul 9, 2024 at 4:05 PM
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STRAILER
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When the key is in the crank position do you have power to the purple wire at the starter?
Jul 11, 2024 at 10:03 AM
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HAILEEGRACE12
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It took me a min to be for sure but there is power but not very much. I hooked it up to a secondary power source to make sure and only getting about 2 volts to the purple wire at the starter when the key is in the crank position.
Jul 11, 2024 at 8:16 PM
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What happens if you put 12 volts to the starter? Also, is the battery good? I would remove the battery and have it checked at the autoparts store. The starter relay is what powers the solenoid when the key is cranked over.
Jul 12, 2024 at 9:14 AM
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HAILEEGRACE12
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I already had the battery check and if I pull the relay and use a jump wire, I can make the starter crank, but it will not start. Cranks really strong but doesn't even try to start up. I even tried it with starter fluid and no change from when I tried without it.
Jul 12, 2024 at 9:18 AM
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HAILEEGRACE12
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I have not tried putting 12v to that purple wire, isn't that just a data line?
Jul 12, 2024 at 9:19 AM
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STRAILER
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If you check the wiring diagrams above, you can see the purple wire goes to the starter solenoid which is the trigger wire.
Jul 12, 2024 at 9:26 AM
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HAILEEGRACE12
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So, is that different from me jumping where the relay goes to get it to crank? Should I just run a line strait from the battery ?
Jul 12, 2024 at 9:48 AM
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Nope if you can jump the relay and it cranks then we are good. Does the security light flash when you crank it over?
Jul 12, 2024 at 9:55 AM
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HAILEEGRACE12
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It flashes as I'm turning the key just once but when I let go the light just stays on continuously. I tried the relearn procedure and first time I tried it, it went from staying on like it is now, to blinking. Then I tried once more and it's back to staying on continuously.
Jul 12, 2024 at 9:57 AM
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HAILEEGRACE12
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So I had a mechanic ( friend of a friend) tell me that I needed a high end scanner then I could erase some codes or something about the passlock ,then I'd have to relearn my key and he said that would fix it...heave you ever heard of that? So since I can get it to crank at the relay, and I'm getting fuel coming out at the rail (shrader valve) to me that would mean it would have to be something either in the security system /anti theft , or in the computer somewhere. I just don't know what else it could be and I'm fairly knowledgeable about cars especially these vortec engines. Any thoughts or advice?
Jul 12, 2024 at 1:34 PM
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STRAILER
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It does sound like a security issue, I would try a hard system reboot to see if the system clears and if so you may need to have the key reprogrammed.

Here is a guide to help:

https://www.2carpros.com/articles/step-by-step-guide-performing-a-hard-system-reboot-for-your-vehicles-electronics-systems

Here is a video for the scanner that you need to retrieve the codes for the security system. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:


https://youtu.be/u-4syLc-ifQ


Please go over these guides and get back to us.

Jul 13, 2024 at 10:07 AM
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HAILEEGRACE12
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Okay, so, I did the hard reboot with no changes then I finally found a high-end CAN scanner but now there's a different issue...the truck will not communicate with either of the 5 scanners I've tried, and I also noticed the little green bar under there gears that indicate which one you are in. Is not there anymore. Is this all linked together? Idk what to do now.
Jul 17, 2024 at 7:16 PM
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STRAILER
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That is a good clue, the gear range sensor could be not working. can you turn the key on without cranking or starting the engine then put the car in reverse to see if the reverse lights come on? Also, with the key on the dark green wire should have power when the car is in park.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here is the location of the gear range sensor and how to change it out if needed.
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Jul 18, 2024 at 10:56 AM
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HAILEEGRACE12
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Okay, I checked to see if the reverse lights were coming on and they are now. This range sensor is the neutral safety switch, the first thing I attempted to replace but from the diagrams u sent, I don't think I did it correctly... It's kind of hard to read that diagram and understand exactly what I did or didn't do. Also, you said the dark green wire should be hot when in park . Are you talking about at the end port?
Jul 19, 2024 at 4:41 PM
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HAILEEGRACE12
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I'm sorry that meant to say the reverse lights are not coming on.
Jul 20, 2024 at 8:03 AM
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STRAILER
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Okay, this means the neutral safety switch is bad or it is not installed correctly. I would check the electrical connector at the switch as well. Yes, the dark green wire should have power when the key is in the crank position. use a test light and probe the wire.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Please go over this guide and get back to us.
Jul 20, 2024 at 10:21 AM
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HAILEEGRACE12
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So, I went and bought a brand new NSS and installed it correctly but with no changes. I'm wondering what else would be the cause of the gear indcater not working and why still have no communication with anything I plug into the obd port. Is there a way I can just bypass this NSS altogether? I know it's not ideal and not the safest thing to do, but no one else will be driving my truck and I don't plan on selling it or anything so if I could just get it back drive able then I could focus on fixing it or anything else for that matter. Unless you have something else better that you think could be the culprit.
Jul 28, 2024 at 2:40 AM
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We must be missing something, so to recap and lets recheck, there is no power at the trigger wire of the starter when the key is in the crank position? There is no security light flashing and you have swapped out the starter relay and check all fuses in the starting system wiring diagrams I give in the first reply?
Jul 29, 2024 at 9:23 AM
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HAILEEGRACE12
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I'm going to do each step again I had my brother helping me last go round so I'm going to double check those things first try soon. Thanks for being patient with me!
Jul 29, 2024 at 10:09 AM
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No problem, that is what we are here for. let me know :)
Jul 29, 2024 at 10:21 AM
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HAILEEGRACE12
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Okay, so, right off I found that the 10A crank fuse is not getting any reading with the key on. I took the fuse out and it's hot on one side, but I put a new fuse in, and that same side isn't hot neither is.
Jul 29, 2024 at 11:29 AM
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STRAILER
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Good find, it looks like the ignition switch is bad which is what powers the crank fuse. But can you also check the IGN A fuse as well the way you checked the crank fuse?
Jul 29, 2024 at 11:32 AM
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HAILEEGRACE12
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Yes, all the other fuses were getting power.
Jul 29, 2024 at 11:46 AM
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HAILEEGRACE12
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Also, I have replaced the ignition switch already as well.
Jul 29, 2024 at 11:46 AM
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Can you please check to see if the red wire into the ignition switch has power when in the crank position?



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Jul 29, 2024 at 12:00 PM
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HAILEEGRACE12
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The red wire is only getting a reading of 5 v.
Jul 29, 2024 at 1:57 PM
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STRAILER
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You can see by the wiring diagrams it should have 12 volts, please check the voltage at the IGNA fuse.
Jul 30, 2024 at 9:29 AM
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HAILEEGRACE12
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Okay, my mistake. yes, the fuse and the red wire are both getting 12 V.
Jul 30, 2024 at 12:30 PM
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HAILEEGRACE12
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Also, the security light is now flashing again. I tried to reset the security and tried the relearn process twice.
Jul 30, 2024 at 12:54 PM
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HAILEEGRACE12
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Not sure if I missed your response or not but do u know if I can just bypass the NSS altogether or do u have any other ideas?
Jul 31, 2024 at 11:19 AM
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STRAILER
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Do you have power when the ignition switch is in crank mode to the yellow and red wire?
Jul 31, 2024 at 11:55 AM
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HAILEEGRACE12
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Yes they both have 12v +
Jul 31, 2024 at 12:02 PM