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Joined: Nov 2008
Posts: 8,663
Campfire Outfitter
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Campfire Outfitter
Joined: Nov 2008
Posts: 8,663 |
I can be of little to zero help if the problem is driven by a computer/pcm/sensor interrupt or failure. If something in that realm is shutting you down, I would be doing the plug in and pray game that many play and probably not winning. Sorry.
Do we have certainty that you have good compression on all cans and proper amount of fuel to cans as well, and more than 12v with normal amps from battery - system properly grounded?
If "yes".
If the starter does not crank, then not getting 12v to the solenoid/starter setup. Why?? Where is the interrupt? If the plugs are not firing (how do I discern this if engine is not cranking?), then not getting sufficient voltage into the coil (why?), or not getting it out (why?) or good voltage from the coil but not getting to plugs (all of them? and why?) My guess is its a shorted module of some sort. Could be anyone as gm links them all together from what ive read and been told. One bad module can cause this, but trying to figure which is where i currently am. Just hoping someone has had this issue pop and had a bit of direction. Its a tough one for sure and i appreciatr everyones input so far There are 4 major food groups, ECM/PCM, ABS, transmission and body modules that would mess with the CAN buss. You’ve already eliminated security lock out. Since you tried a new ECM/PCM and failed I would look to the transmission module as that one has both a limp mode and kill switch. ABS normally won’t lock you out but a shorted one could mess with the CAN buss. Go one at a time.
Swifty
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Joined: May 2019
Posts: 115
Campfire Member
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Campfire Member
Joined: May 2019
Posts: 115 |
There is no shortcut to this problem. You need a factory wiring diagram. There are probably multiple powers and grounds to The PCM and maybe other modules as well. You need to start with a wiring diagram. You can purchase a sub to the on line auto diag. web sites , like ALData.
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Joined: Aug 2010
Posts: 28,118 Likes: 2
Campfire Ranger
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Campfire Ranger
Joined: Aug 2010
Posts: 28,118 Likes: 2 |
There is no shortcut to this problem. You need a factory wiring diagram. There are probably multiple powers and grounds to The PCM and maybe other modules as well. You need to start with a wiring diagram. You can purchase a sub to the on line auto diag. web sites , like ALData. Yes and get correct one for drivetrain
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Joined: Mar 2010
Posts: 11,829 Likes: 10
Campfire Outfitter
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OP
Campfire Outfitter
Joined: Mar 2010
Posts: 11,829 Likes: 10 |
I can be of little to zero help if the problem is driven by a computer/pcm/sensor interrupt or failure. If something in that realm is shutting you down, I would be doing the plug in and pray game that many play and probably not winning. Sorry.
Do we have certainty that you have good compression on all cans and proper amount of fuel to cans as well, and more than 12v with normal amps from battery - system properly grounded?
If "yes".
If the starter does not crank, then not getting 12v to the solenoid/starter setup. Why?? Where is the interrupt? If the plugs are not firing (how do I discern this if engine is not cranking?), then not getting sufficient voltage into the coil (why?), or not getting it out (why?) or good voltage from the coil but not getting to plugs (all of them? and why?) My guess is its a shorted module of some sort. Could be anyone as gm links them all together from what ive read and been told. One bad module can cause this, but trying to figure which is where i currently am. Just hoping someone has had this issue pop and had a bit of direction. Its a tough one for sure and i appreciatr everyones input so far There are 4 major food groups, ECM/PCM, ABS, transmission and body modules that would mess with the CAN buss. You’ve already eliminated security lock out. Since you tried a new ECM/PCM and failed I would look to the transmission module as that one has both a limp mode and kill switch. ABS normally won’t lock you out but a shorted one could mess with the CAN buss. Go one at a time. Chit, completely forgot about the trans module
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Joined: Mar 2010
Posts: 11,829 Likes: 10
Campfire Outfitter
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OP
Campfire Outfitter
Joined: Mar 2010
Posts: 11,829 Likes: 10 |
There is no shortcut to this problem. You need a factory wiring diagram. There are probably multiple powers and grounds to The PCM and maybe other modules as well. You need to start with a wiring diagram. You can purchase a sub to the on line auto diag. web sites , like ALData. Buddy has aldata. He sent me a couple schematics, but i need more. Always enjoy working through these problems, but with work, im about to throw in the towel and tow it to his shop lol
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Joined: Jun 2020
Posts: 1,806
Campfire Regular
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Campfire Regular
Joined: Jun 2020
Posts: 1,806 |
x2 on trying to start in neutral, or at least put it in gear and then back into park. There’s a couple safety systems that prevent you from starting it if it thinks it’s in gear.
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Joined: May 2019
Posts: 115
Campfire Member
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Campfire Member
Joined: May 2019
Posts: 115 |
I don't remember which years this applies to but there's a ground behind the P/S pump that likes to rot off. Worth a check.
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Joined: Dec 2008
Posts: 77
Campfire Greenhorn
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Campfire Greenhorn
Joined: Dec 2008
Posts: 77 |
Does the check engine light come on when you turn the key on?
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Joined: Jul 2011
Posts: 6,170
Campfire Tracker
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Campfire Tracker
Joined: Jul 2011
Posts: 6,170 |
Sounds like your troubleshooting is pretty complete, but with the mouse problem another wire or 3 might have been overlooked.
Damn that soy based wire insulation. I have to repair wires on my ATV about every 18 months.
Oh yeah, there is a 12v connection post to the right of the batt. when looking from the front. It's for all kinds of garbage to be connected to. I had trouble with that connection once. I thought the same thing. There are more wires chewed through somewhere. OP did you test continuity AFTER you did the wire repairs?
Last edited by smarquez; 09/11/23.
Fight fire, save lives, laugh in the face of danger.
Stupid always finds a way.
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Joined: Mar 2010
Posts: 11,829 Likes: 10
Campfire Outfitter
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OP
Campfire Outfitter
Joined: Mar 2010
Posts: 11,829 Likes: 10 |
Does the check engine light come on when you turn the key on? Yes, all dash icons do
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Joined: Mar 2010
Posts: 11,829 Likes: 10
Campfire Outfitter
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OP
Campfire Outfitter
Joined: Mar 2010
Posts: 11,829 Likes: 10 |
Sounds like your troubleshooting is pretty complete, but with the mouse problem another wire or 3 might have been overlooked.
Damn that soy based wire insulation. I have to repair wires on my ATV about every 18 months.
Oh yeah, there is a 12v connection post to the right of the batt. when looking from the front. It's for all kinds of garbage to be connected to. I had trouble with that connection once. I thought the same thing. There are more wires chewed through somewhere. OP did you test continuity AFTER you did the wire repairs? Yes on continuity. Cant be 100% sure i didnt miss something, but i spent a fee hours pulling harnesses and tracing everything out. Only chewed wires were directly under the fuse box
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Joined: Jul 2011
Posts: 6,170
Campfire Tracker
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Campfire Tracker
Joined: Jul 2011
Posts: 6,170 |
Did it look like there was mouse piss on the fuses inside the fuse box? If so there could be corrosion inside the fuse holders. Saw it on a Youtube video. The fix was a new fusebox.
Fight fire, save lives, laugh in the face of danger.
Stupid always finds a way.
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Joined: Oct 2013
Posts: 18,930 Likes: 1
Campfire Ranger
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Campfire Ranger
Joined: Oct 2013
Posts: 18,930 Likes: 1 |
Possible faulty ignition switch??
The last time that bear ate a lawyer he had the runs for 33 days!
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Joined: Jan 2010
Posts: 3,989
Campfire Tracker
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Campfire Tracker
Joined: Jan 2010
Posts: 3,989 |
Have you checked the coils ground wire. Runs from a harness under the front diff. Saw it could be a problem from another forum.
“No one in hell can ever say I went to Christ and He rejected me.
C.H. Spurgeon
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Joined: Mar 2010
Posts: 11,829 Likes: 10
Campfire Outfitter
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OP
Campfire Outfitter
Joined: Mar 2010
Posts: 11,829 Likes: 10 |
Have you checked the coils ground wire. Runs from a harness under the front diff. Saw it could be a problem from another forum. Checked every ground i could find and tested resistance on the grounds to the battery just to see if any had a higher reading. May have to look for that one specifically
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Joined: Jul 2005
Posts: 1,785
Campfire Regular
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Campfire Regular
Joined: Jul 2005
Posts: 1,785 |
Have you burnished all the ground points at the engine block, including the starter base? I know from experience that a ground that looks fine, isn't.
I have a full set of shop manuals for that truck. If it would help, I could scan and email that troubleshooting section to you.
Last edited by 3584ELK; 09/12/23.
"I didn't realize we had so many snipers in this country." by J23
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Joined: Feb 2020
Posts: 2,789 Likes: 1
Campfire Regular
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Campfire Regular
Joined: Feb 2020
Posts: 2,789 Likes: 1 |
Due to the increased price of ammo, don't expect a warning shot...
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Joined: Oct 2013
Posts: 18,930 Likes: 1
Campfire Ranger
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Campfire Ranger
Joined: Oct 2013
Posts: 18,930 Likes: 1 |
Yeah because they never have any issues at 20 years old.
The last time that bear ate a lawyer he had the runs for 33 days!
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Joined: Mar 2010
Posts: 11,829 Likes: 10
Campfire Outfitter
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OP
Campfire Outfitter
Joined: Mar 2010
Posts: 11,829 Likes: 10 |
Update. So was messing with the truck while my guys were at lunhc and found a couple more chewed wires in a harness under the fuse box. Found it by cutting back the loom. Never got in there because it didnt seem there was anyway a mouse could have got in there. Well fixed those 4 wires and still nothing. What changed though is I had a buddy turning the key to crank while iw as moving things again and it started to crank for about 2 seconds. Someone had mentioned earlier in here that mouse piss could ruin a fuse box. Im thinking that is exactly what has happened. Going to order a new fuse box and replace that and see what happens
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Joined: Oct 2013
Posts: 18,930 Likes: 1
Campfire Ranger
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Campfire Ranger
Joined: Oct 2013
Posts: 18,930 Likes: 1 |
Get that thing going and trip it to some other poor soul.
The last time that bear ate a lawyer he had the runs for 33 days!
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