SOLVED! 2005 Envoy 4.2L XUV doesn't want to turn off

[Moms_Spaghetti]

Some backstory: (takes place over 3-4weeks)
I bought the XUV with my roommate back in March. It has some “aftermarket switches” one for the tailgate window and another to open the tailgate. COVID happened so we had to be sent home from school and we had not been able to drive it till the end of July. When we got back, we have had the rack and pinion replaced and had an issue with the tailgate “fixed” at a local mechanic.

Since then we had an issue with the car not completely turning off the battery. We I found out later that the “Solution” aka zip tie that the previous owner had on the Ignition lock cylinder actuator had slipped off. This “solved” our battery light staying on issue until a week later.

I’m driving about 30mins and notice the AC is not switching from my feet and nothing is fixing it. I pull over to restart the car but it wont turn over. Luckily, I bought a jump kit and it turns over quickly and I am on my way. 2 mins later it dies while I am driving 20mph. I jump it again but wait 20mins for the alternator to charge the battery again I ride for about 15mins with nothing on it dies as I am merging onto a highway. I jump it about 3 more times before I find a spot to park it and go buy a new battery. It turns over right away with the new battery and I get it home with no problems.
Backstory done:

A week passes and one day it does not turn off. Like key turns completely off and is out, but I can shift the car in D and drive off if I wanted too. We first “erroneously” unplugged the battery and rolled up all the windows at the same time to kill the engine. We tried to restart, but it would not turn over, it gave us a P2101 code.

We took out the throttle body and cleaned it in hopes that it would clear the code, but just in case we purchased a new throttle body. It turned over and sounded much better, but still did not turn off. This time we pulled the fuel pump relay to shut it off.

Since then we have replaced the ignition switch, but nothing changed. I have also taken out the key cylinder and cleaned it with no results. The ABS light stays on constantly and the check engine light will come on after we pull the fuel pump relay but is gone the next day. We have noticed that the Fuel pump relay gets extraordinarily hot after driving for a bit (15-20mins) We are pretty sure its something electrical maybe bad wiring, but that is all we can think of at this point. Looking for any direction or advice.

 

[Mooseman]

Did find this one thread:

'03 Envoy will not shut off. Not the ignition switch. Need Help!

I need some help. I have a 2003 GMC Envoy SLT 4x4, I6 engine with 148k on it. It will not shut off. I have changed the ignition switch twice, checked the second new one with a test light to determine it was not the culprit. It started as I walked out to get into my truck and noticed the check...

gmtnation.com

Likely something backfeeding into the PCM. Try the method mentioned in that thread.

 

[Moms_Spaghetti]

Thanks for the response Mooseman! I gave it a shot, but it still didn't turn off. I did notice that Fuses 10, 22 & 28 (PCMB / IGN E / PCM I) caused the throttle body to Cycle? make a flutter noise? It makes that same noise right when we first reconnect the battery. So I think the signs point back to the PCM backfeed like you said. Any tips on where/how i should start looking?

 

[Mooseman]

Check your grounds. I think I remember somebody that had a similar issue but the high beams would kill the engine and it turned out to be a ground.

Electrical Ground locations

 

[TJBaker57]

I did notice that Fuses 10, 22 & 28 (PCMB / IGN E / PCM I) caused the throttle body to Cycle?

Was the key OFF when you checked these fuses and the throttle body cycled??? Fuse 28 and fuse 22 should have NO POWER when the key is off and as such there should be no cycling of anything when pulling and replacing these 2 fuses with the key off.

 

[Moms_Spaghetti]

Was the key OFF when you checked these fuses and the throttle body cycled??? Fuse 28 and fuse 22 should have NO POWER when the key is off and as such there should be no cycling of anything when pulling and replacing these 2 fuses with the key off.

No, It was off and the key wasn't in the ignition at all. We just had the battery connected and we were pulling fuses. I haven't been able to check the grounds yet. Im waiting on a friend to borrow his multimeter because all i have is a light probe.

 

[TJBaker57]

No, It was off and the key wasn't in the ignition at all. We just had the battery connected and we were pulling fuses. I haven't been able to check the grounds yet. Im waiting on a friend to borrow his multimeter because all i have is a light probe.

OK,, so let me explain this maybe a little clearer this time. You pulled these fuses #22 and #28 while they key was OFF and the throttle cycled. This proves there was power to these fuses when there should not be power there at all. The power to these 2 fuses comes through the ignition switch. If there is power to these fuses when the key is off then there is a problem at the ignition switch. My guess is the switch is not properly aligned and is not truly in the OFF position. You need to use your test light and test the wires coming from the ignition switch to see why you have power when you should not have power. Do you have the ignition switch wiring diagram?

 

[TJBaker57]

Here's a test you can do with the test light. Look at this diagram...



At the ignition switch, with key OFF test for power at the white, orange, yellow, brown, and pink wires. There should be no power there and the test light should not light up. If it does light up at any of these wires, pull the fuses #34 and #36. From the diagram you can see these 2 fuses supply power to the ignition switch. Now test those same 5 wires for power. if you had power there before you oulled the fuses #34 & #36 and you don't have power there now then the trouble is at the ignition switch. If you continue to have power to any of these wires after removing the fuses #34 and #36 then you have a 'backfeed' as @Mooseman suggested.

A backfeed most often happens when someone installs some aftermarket equipment like a radio or lighting system and wires that stuff incorrectly. Does the truck look to have some add-on things like a light bar or aftermarket audio equipment?

 

[Moms_Spaghetti]

Here's a test you can do with the test light. Look at this diagram...

View attachment 96696

At the ignition switch, with key OFF test for power at the white, orange, yellow, brown, and pink wires. There should be no power there and the test light should not light up. If it does light up at any of these wires, pull the fuses #34 and #36. From the diagram you can see these 2 fuses supply power to the ignition switch. Now test those same 5 wires for power. if you had power there before you oulled the fuses #34 & #36 and you don't have power there now then the trouble is at the ignition switch. If you continue to have power to any of these wires after removing the fuses #34 and #36 then you have a 'backfeed' as @Mooseman suggested.

A backfeed most often happens when someone installs some aftermarket equipment like a radio or lighting system and wires that stuff incorrectly. Does the truck look to have some add-on things like a light bar or aftermarket audio equipment?

Wow thank you TJ! That Diagram is much clearer than the one i was using! I will give that a shot later today and update you! When i got the car there was an aftermarket stereo, but I didn't notice a problem before? The previous owner had a switch installed for the tailgate window. We also had a local mechanic recently(June) install a switch on the inside of the tailgate to drop it since the normal button wasn't working. So I have been thinking one of those 3 seems suspicious and has something to do with my problem.

 

[Moms_Spaghetti]

So i checked with my probe and no light came on any of the wires before-start. After i started it up all wires lit up except for yellow. After an attempt at shutdown only (Red&white/ Red / Pink) stayed on pulled(Fuse 34= red wire turned off) (Fuse 36 = Red & white wire turned off) Now only pink lighting up. So i guess that means there is a back feed somewhere? Where should I start looking?

 

[Mooseman]

When you turn the key to OFF, pull the connector to the ignition switch and see if things turn off. It it keeps running and there is still power where there shouldn't be at the connector, you'll have to backtrace according to the schematics to find this backfeed.

 

[TJBaker57]

Wow thank you TJ! That Diagram is much clearer than the one i was using!

Follow this link and download the service literature, sounds like you will need these schematics to get to the bottom of this....

Need service manuals? Get them here!

*********************************************************** The password below is no longer required. I am unable to edit that post to remove that info. Please note that the FireFox browser has issues with the password handling and because these downloads are not under HTTPS, flagging them as...

gmtnation.com

 

[TJBaker57]

So i checked with my probe and no light came on any of the wires before-start. After i started it up all wires lit up except for yellow. After an attempt at shutdown only (Red&white/ Red / Pink) stayed on pulled(Fuse 34= red wire turned off) (Fuse 36 = Red & white wire turned off) Now only pink lighting up. So i guess that means there is a back feed somewhere? Where should I start looking?

So just to be certain... The pink was dead before startup but went live at key on and stayed live with key off, right?

Mooseman has already given you the next step which is pulling the ignition switch connector off to see if that 'phantom' power is coming from the switch or the pink wire.

 

[Moms_Spaghetti]

When you turn the key to OFF, pull the connector to the ignition switch and see if things turn off. It it keeps running and there is still power where there shouldn't be at the connector, you'll have to backtrace according to the schematics to find this backfeed.

So just to be certain... The pink was dead before startup but went live at key on and stayed live with key off, right?

Mooseman has already given you the next step which is pulling the ignition switch connector off to see if that 'phantom' power is coming from the switch or the pink wire.

Just tried again with the key and switch in the off position then pulled the connector off, but The car stayed running

I will start my search down this pink wire!

 

[TJBaker57]

Just tried again with the key and switch in the off position then pulled the connector off, but The car stayed running

I will start my search down this pink wire!

Well that's another clue that needs evaluation. When you pulled off the connector did you test for power at the pink wire and also the terminal on the switch that it goes into? Because if I'm thinking correctly this ~might~ mean the trouble is in the switch.

EDIT: No, I'm not thinking this through yet. It takes this old brain some time!!

 

[budwich]

this is funny as this forum usually gets the "car won't start" posts by the "hundreds".... but rarely, we can't turn the dam thing off....

My suggestion is take a picture of your fuse block for reference.... cause you will likely need it for later. Get you car going just as you did in the previous post with everything there in terms of fuses and the ignition switch connector. Turn the ignition OFF... hopefully the car stays running, right? IF so, plug the switch connector, does the car stay running? IF yes, go to the fuse block and start pulling fuses BUT be some what "smart" by first choosing ones that have not thing to do with the engine... things like horn, AC, radio, etc... you get the idea. Keep pulling and don't put them back. Eventually, hopefully you only have fuses specific to running which you can start pulling. You probably know which ones those are right now. Once you find a "killer fuse", while still leaving any previous ones pulled, try to restart the vehicle.... if no restart, put the last fuse back and try restart. Hopefully, the process may narrow finding any "back feed circuits"... maybe.

One needs to look at the fuse box / cover for labeling for which fuses are for which function to narrow down things.

 

[TollKeeper]

Im curious to know what stays on, besides the engine, when the key is turned off. Radio? Power Windows/Locks? Heat/AC?

 

[Moms_Spaghetti]

this is funny as this forum usually gets the "car won't start" posts by the "hundreds".... but rarely, we can't turn the dam thing off....

My suggestion is take a picture of your fuse block for reference.... cause you will likely need it for later. Get you car going just as you did in the previous post with everything there in terms of fuses and the ignition switch connector. Turn the ignition OFF... hopefully the car stays running, right? IF so, plug the switch connector, does the car stay running? IF yes, go to the fuse block and start pulling fuses BUT be some what "smart" by first choosing ones that have not thing to do with the engine... things like horn, AC, radio, etc... you get the idea. Keep pulling and don't put them back. Eventually, hopefully you only have fuses specific to running which you can start pulling. You probably know which ones those are right now. Once you find a "killer fuse", while still leaving any previous ones pulled, try to restart the vehicle.... if no restart, put the last fuse back and try restart. Hopefully, the process may narrow finding any "back feed circuits"... maybe.

One needs to look at the fuse box / cover for labeling for which fuses are for which function to narrow down things.

I will try the fuses after class today and update you on what I find.

Im curious to know what stays on, besides the engine, when the key is turned off. Radio? Power Windows/Locks? Heat/AC?

So the A/c and blower turn off like the should and come on when i turn the key to on. Windows work when i turn to accessory. They all stop working as they should when key is turned to off. only thing that stays on is the radio, but I believe it is on a timer to when it shuts off?

EDIT: So the radio was on the second I connected the battery. I didn't even have the keys in the ignition yet!

I did try to put it in gear when key was in off position, and the shifter moved but i didn't hear the transmission shift and the car stayed in park.

 

[TJBaker57]

What can you tell us about these switches added to operate the endgate? Do you know what terminals or wires they are connected to? Any time you start putting power to places and from places that aren't part of the original design it's a risk.

 

[Moms_Spaghetti]

What can you tell us about these switches added to operate the endgate? Do you know what terminals or wires they are connected to? Any time you start putting power to places and from places that aren't part of the original design it's a risk.

Unfortunately no I don't know what/how they are connected we got the car with these switches. I know one works for the back window the other one "was" used for the wipers(they are fixed now), and they are both on the panel above my left knee. There is another button switch that is on the tailgate itself that releases the the drop down on the tailgate.

I will take some pictures later

 

[budwich]

I think you just need to trace the powering for the radio. I don't believe disconnecting / connecting a battery without a key will turn on a radio. You could try the same test with the ignition switch disconnected and see what the result is.

This is going to be an ugly problem. Related to the my earlier post and also the other subsequent question that tollkeeper posed (what stays on with the key out / off?)... with the key off and maybe even ignition switch disconnected, but battery connected. Pull or check each fuse position for voltage in the engine box. make a note of which has powering, then some one can go thru the power / ground schematics to find which fuse had power and whether it should. Long process but again might help.

 

[TJBaker57]

A quick look at wiring diagrams appear to indicate the radio is always powered.... "Hot at all times".

To me this would suggest it is perhaps the body control module that is getting a power source when it should not and enabling the radio via class 2 bus??

 

[Moms_Spaghetti]

Okay so I pulled the fuses and not surprisingly (10, 22, 28) caused it to shutoff
10 = Powertrain control Module B
22 = Ignition E
28 = Powertrain Control Module 1
23 = *Electronic throttle Control (didn't turn off just caused it to run really rough)*

I pulled a select few in the Rear under seat fuse-box. (but nothing out of the ordinary)
(41 = Radio / 47 = Ignition 0)
So I feel like since the PCM controls alot of stuff this really didn't Narrow it down that much

 

[TJBaker57]

Okay so I pulled the fuses and not surprisingly (10, 22, 28) caused it to shutoff
10 = Powertrain control Module B
22 = Ignition E
28 = Powertrain Control Module 1
23 = *Electronic throttle Control (didn't turn off just caused it to run really rough)*

I pulled a select few in the Rear under seat fuse-box. (but nothing out of the ordinary)
(41 = Radio / 47 = Ignition 0)
So I feel like since the PCM controls alot of stuff this really didn't Narrow it down that much

So, have you looked at the wiring diagrams yet? Do you see the clue here? You pull out fuse 22 and the engine dies..... Why?? Look at what fuse 22 supplies....



Fuse 22 supplies headlight switches, brake light switches, turn signal switch, park neutral switch, AC relay..... Anything engine related? Not that I see. So why would that kill the engine? What if something is supplying power to something that is ~supposed~ to be powered by fuse 22? A wire shorted to power "downstream" of fuse 22 will feed backwards (backfeed) through fuse 22 and if you follow it back it will lead right back to fuse 28 (not the one seen in the previous screenshot but another page of the schematics) that supplies power to the coils and injectors and all the way back to that pink wire at the ignition switch.

I'm not saying this is for sure the issue but it bears investigation. Start it up, shut the key off, pull fuse 22. If the engine dies like before, with fuse 22 still out, check for power at each side of the socket of fuse 22. Unless your test light probe is very thin you will need to stick a thin piece of wire or something that will fit down inside the socket without forcing it. There should be no power at either side of that socket with the key off.

 

[TJBaker57]

Another thing I've been thinking of,,, you have had multiple electrical issues leading up to this issue of not shutting down. You may have some wire(s) overheated in a harness and have fused together. Some well thought out and documented testing with a multimeter can help confirm and perhaps isolate this.

 

[gmcman]

Forgive me if I missed it, but have you tried replacing the ignition switch?

 

[TollKeeper]

Switch was not replaced, but when taken out, the engine still runs.

 

[gmcman]

Correct me if I'm wrong, but doesn't the switch internally make the necessary connections and dis-connections within the circuit to energize and de-energize what's needed to shut the engine off as well as other accessories?

I would try one since they are inexpensive and/or ensure the position is correct on the gear teeth.

Wasn't there a zip tie discovered in there?

 

[TJBaker57]

Forgive me if I missed it, but have you tried replacing the ignition switch?

1st post states the ignition switch replaced.

 

[TJBaker57]

Correct me if I'm wrong, but doesn't the switch internally make the necessary connections and dis-connections within the circuit to energize and de-energize what's needed to shut the engine off as well as other accessories?

I would try one since they are inexpensive and/or ensure the position is correct on the gear teeth.

Wasn't there a zip tie discovered in there?

I actually yesterday took a new switch apart and tested the inner workings! It comprises 2 separate switching circuits. Terminals A,B,&C is a single pole two position where B is common and A and C connect and disconnect to B as required. Terminals D,E,F,&G have F as common (powered) and terminals E,G, and D connect and disconnect as required, shown in the wiring diagrams. For anyone interested here are the connections in the order they occur as one turns the key slowly...

 

[gmcman]

1st post states the ignition switch replaced.

I did read this whole thread, should have had my coffee first.

Maybe the last switch was installed incorrectly in regards to the gear teeth and this one went back in the same manner?

Just tossing out ideas.

I can see how removing the switch should in theory would shut everything down, but I haven't dived into the entire circuit.

 

[gmcman]

Ok, sorry for taking this thread on a detour....I woke up, saw the thread, and had it in my head the engine wouldn't shut off I obviously scrolled past some key points while sleeping......my bad.

 

[TJBaker57]

Ok, sorry for taking this thread on a detour....I woke up, saw the thread, and had it in my head the engine wouldn't shut off I obviously scrolled past some key points while sleeping......my bad.

No detour in my eyes! Far too often I find myself suffering tunnel vision and endlessly chasing down what turns out to be the wrong path while overlooking things obvious to others. Best practice is to consider all possibilities.

 

[budwich]

I did read this whole thread, should have had my coffee first.

Maybe the last switch was installed incorrectly in regards to the gear teeth and this one went back in the same manner?

Just tossing out ideas.

I can see how removing the switch should in theory would shut everything down, but I haven't dived into the entire circuit.

I think ultimately that you missed the last few tests that has the truck running with the switch totally disconnected / unplugged. It is unlikely to be a switch problem. It is either wiring issues OR the lower portion of the fuse box has some "bonded" tracks that shouldn't be that way... potentially the result of maybe bad wiring causing excess current / heating. I think there have been some posts of people having issues with the lower "half" of the fuse box having "fused tracks" which were readily visible upon inspection.

 

[Moms_Spaghetti]

I did read this whole thread, should have had my coffee first.

Maybe the last switch was installed incorrectly in regards to the gear teeth and this one went back in the same manner?

Just tossing out ideas.

I can see how removing the switch should in theory would shut everything down, but I haven't dived into the entire circuit.

So yeah i thought of this too and re installed it both ways moving the gear forward a few teeth and reinstalling & moving it back a few teeth but no such luck.

So, have you looked at the wiring diagrams yet? Do you see the clue here? You pull out fuse 22 and the engine dies..... Why?? Look at what fuse 22 supplies....

View attachment 96707

Fuse 22 supplies headlight switches, brake light switches, turn signal switch, park neutral switch, AC relay..... Anything engine related? Not that I see. So why would that kill the engine? What if something is supplying power to something that is ~supposed~ to be powered by fuse 22? A wire shorted to power "downstream" of fuse 22 will feed backwards (backfeed) through fuse 22 and if you follow it back it will lead right back to fuse 28 (not the one seen in the previous screenshot but another page of the schematics) that supplies power to the coils and injectors and all the way back to that pink wire at the ignition switch.

I'm not saying this is for sure the issue but it bears investigation. Start it up, shut the key off, pull fuse 22. If the engine dies like before, with fuse 22 still out, check for power at each side of the socket of fuse 22. Unless your test light probe is very thin you will need to stick a thin piece of wire or something that will fit down inside the socket without forcing it. There should be no power at either side of that socket with the key off.

I was in labs all day today so I just got to this! I tried what you said and yes in the off position Fuse 22 was still getting power through it, my probe lit right up!

I also had a friend stop by and he tried his code reader on it. There was no engine light on but it pulled 3 codes.

P0740
P0785
P2761

I'm not sure if they are related or something due to me pulling a lot of fuses recently. Or part of my problem.

 

[TJBaker57]

Maybe the last switch was installed incorrectly in regards to the gear teeth and this one went back in the same manner?

I had precisely the same thoughts at one time. But when he pulled the harness connector off the switch and it kept running that trashed that idea!

 

[TJBaker57]

So yeah i thought of this too and re installed it both ways moving the gear forward a few teeth and reinstalling & moving it back a few teeth but no such luck.



I was in labs all day today so I just got to this! I tried what you said and yes in the off position Fuse 22 was still getting power through it, my probe lit right up!

I also had a friend stop by and he tried his code reader on it. There was no engine light on but it pulled 3 codes.

P0740
P0785
P2761

I'm not sure if they are related or something due to me pulling a lot of fuses recently. Or part of my problem.

I think these pending codes are the result of the ignition switch cutting off power to fuse 47 as it should when turned off,,, but the backfeed is keeping the pink wire live so the engine keeps running,,, and the codes come up as a result of the engine still running but with no power to any of the transmission solenoids (they are powered by fuse 47) due to the ignition switch cutting off power to those solenoids. I need to read that ramblimg sentence over again, did it make sense?

 

[TJBaker57]

yes in the off position Fuse 22 was still getting power through it, my probe lit right up!

Next is to determine which side of fuse 22 is the power coming from. From the ignition switch side or the other side? Got a blown fuse handy? Put that in there and you can use your test light on each side to see which side is the power coming from.

 

[mrrsm]

This information about the "cluster of the PXXX Codes" you reported in Post #35 is very interesting:

Rick's Free Auto Repair Advice

Rick's Free Auto Repair Advice has over 1,500 auto repair and information articles for DIYers and car owners.

ricksfreeautorepairadvice.com

 

[Moms_Spaghetti]

Next is to determine which side of fuse 22 is the power coming from. From the ignition switch side or the other side? Got a blown fuse handy? Put that in there and you can use your test light on each side to see which side is the power coming from.

Okay since I don't have a blown fuse I just used individual wires in the spot of fuse 22 instead, and I found out that power is only coming from the top connection of the fuse (The side with the "Red + white circle" in the attached picture) I am not sure if that means power is coming from up or down stream?