My 2006 Envoy Denali stops running suddenly and then refuses to start

Asked by Aug 30, 2014 at 08:33 AM about the 2006 GMC Envoy Denali

Question type: Maintenance & Repair

The engine quit while driving on the highway.  Both check engine lights came on.  After 45 minutes while waiting for a tow the car started.  Dealer replaced the ignitions switch (shorted) and computer reprogrammed for "driveability".  The throttle body had been replaced about 6 months before.  After repairs exact same problem occurred.  Second tow to the dealer and resultant "loose connector on main outlet from fuse box".  Picked car up and got 10 miles before same problem occurred.  Any ideas.

25 Answers


Don't Sell it. Trade it in. Once you get into running take it to a dealer that didn't work on it.

4 people found this helpful.

This is a serious problem with this truck the dealers are guessing and guessing wrong people are replacing ignition switches, fuses boxes computers, and after 10 mins of driving same problem, will I fix the issue by powering up the fuses that was not getting power when truck would not crank and all tap of difference codes would appear and disappear when starts, in my truck those fuse are # 31 55 23 26 54 56 30 and I power up this fuses by taking power from a open J case fuses ran a wire from j case fuse to fuses # 31 and it power up all the fuses above then I had to power up the fuel pump relay by using a 30amp fuse and using power source between fuse # 27 and 29 it comes on when you turn the key open and off when you turn off and then I removed the pcm fuses, fuses # 10 in my truck and my truck has never ran better does cut off.

4 people found this helpful.

Check the fuse box under the hood. I had the same problem I replaced it with a new one to fix the problem. When it heats up one of the copper wires inside the fuse box comes disconnected I tried soldering the wire but it just happend again. I recommend replacing with new.

7 people found this helpful.

Did you ever get it figured out


Which wire is the one that needs to be solder under the fuse box? I called dealer they want $750 for a new fuse box

3 people found this helpful.

Replaced Engine Computer. My problem is that car shuts off after being on for 20-30 minutes. After that, it either cranks with no start or it stays on, but you get throttle body codes along with ignition switch codes. Also, reduce power and misfires. You can feel the car trying to shut off and won't run properly. Also, on digital climate control. temperature outside reads 50 degrees when this is happening. I'm going to change the FUSE BOX in the engine compartment or add a power that is missing incase that's the problem. Anyone else fix this with replacing fuse box?

4 people found this helpful.

New Programmed Engine computer did not fix problem. Forgot to add that.


Was this issue ever figured out? I'm having same problems on 2006 envoy. Driving down the road and just shuts down. I can wait and it starts back up. Was it the 20 gauge wire in jukebox under the hood? Please help

2 people found this helpful.

Fuse box lol not jukebox.


Hey Guruczd2l I replaced the computer that was the issue I replaced fuse box 1st then it was same issue So just replace the computer!!

1 people found this helpful.

Im having the same problem with my GMC Envoy Denali I thougbt it was a fuel pump or filter issue till I noticed no matter how much fuel injector cleaner or starting fluid i used it didnt start till the temp guage came down all the way down then it fires up. 45-60min

4 people found this helpful.

Hey Guru5R3ZT did the computer work?


Jay it did work look for the right computer on ebay they are overpriced so look for it in multiple junk yards

2 people found this helpful.

What engine you have? I have the 5.3 Ive been reading alot of forums a lot of different answers. It seems like a fuel pump issue as I've been driving with a missfire but it didnt start shutting off with the double check engine light untill installed a new battery. I will look into the computer at junkyards thanx!!


I'm having the same issue with an 05 Envoy Denali...the mech informed me that the computer was no good.. Waiting to get estimate for a new and one pulled from junkyard...any idea on how much I'm looking at

4 people found this helpful.

mine just went out today and its at the shop and they can't figure it out either. they went with the ignition switch no go. My symptoms are while driving to lowes about to park the car just shut down completely and coasted into parking spot. If this is a voltage problem in the fuse box someone should be able to prove this. I am going to the shop tomorrow to give a hand. I worked 42 years in avionics and a/p mechanic on aircraft and my problem is I don't have schematics. all these stupid systems came from aviation with data buses and modules to do the stupidest of things. One computer talks another and he talks to another. I offered my assistance in finding the real problem. I'm going to try helpfulname idea since it makes the most sense to me and along with GuruKPZK as well. I believe this is a voltage problem that for some reason something is shutting down the buses needed to run systems. I can not believe so many people are having the same problem with GMC products and there is not clear cut answer. I volunteered my services to trouble shoot my own car and try to put an end to this ridicules and dangerous problem. My car just shut down like that thank god I was in a lowes parking lot. If this happens to you on a busy highway or something people can get killed. I will update as I go along if they allow me to help and use their schematics and tools to find this dangerous problem.

2 people found this helpful.

I was told the ecu went bad which is also a common thing with our cars. The problem I'm having is everyone is over charging for them because they can't keep them in stock.


almost 4 weeks now my 06 envoy with the same exact problem has been in the shop. They have replaced ignition even though I told them you all tried that not help. they ordered used EEC computer and first one would not program and the second would not take the vin number. they got a new one and programmed it but was not problem. Next they thought body control module they tried a used one and would not communicate with car. they bought a new one and have not plugged it in yet because they don't want to take the chance of the fuse box or whatever the problem will not hurt it. He is now looking in the fuse box as well. I understand this is a problem no one has really figured out because it could be one of three problems mentioned in here. I believe the problem with the copper wire under the fuse box could be the issue because he said every-time he moves the harness to the fuse box it will start or not start and gauges I guess to come up. This is the first car I ever sent out to have worked on. I have been an aircraft mechanic and electronic tech avionics for 43 years and always worked on my own cars. I had one of those weeks where everything was breaking, my dodge 05 stratus would start but no power door locks radio all things that the body control module operates. I had changed the fuse that was bad with new one but no help. I tell you this because always ohm them dont just take out of box assume it is good. I had tore up that car and all things led me back to the fuse I changed. I pulled fuse and looked good but when I ohmed this time it was open. I picked a bad fuse out of a china made kit and it cost me so much time when I had it fixed already but got lazy. with that and other problems my envoy died at lowes so had to have towed. I thought I have to fix so much other stuff I am going to farm this out for once. I am happy I did because these guys are determined to find this problem. I don't think its a matter of money to them now. Like me I have to know so they are going to let me help them troubleshoot this. I have to know what the hell can cause this kind of problem on a perfectly good car. one second its running perfect next what I have to junk it? I am going over in the morning with the info you guys gave me and what else I found and get my car back with an answer. helpfulname you give me hope you must know what your doing with you going through all that. I believe I will try that first. Ill get back I hope with my cars problem.

1 people found this helpful.

did the originator of this question ever get his fixed and what was it?

2 people found this helpful.

I have finally figured out what is causing the problems with all your GMC cars not starting or dying while driving. The problem is the system is such a piece of junk anything can cause this to happen and I will explain. I have been troubleshooting jets for 43 years and when my envoy died I wanted to get to the bottom of this. I know now why this is such a big problem and there is no one answer because its a digital piece of junk. In my case the car just died going to lowes moving slow and out of no where it died. could not get it restarted and 2 shops spent a total of 4 weeks trying to fix it (I was up to my neck in other car repairs at the time so I figured I get lazy and let them fix it but that was a mistake. There are so many questions on the web and partial answers where it can confuse the hell out of anyone. I will tell you my issue and explain why it is so hard to find and repair. This was the hardest problem I had ever dealt with in a car and with all my experience if it took me 1 week to learn and figure out the system I can't imagine someone without electronic experience to ever fix. Ok here we go! first I noticed i was getting pretty much nothing but front windows lights and other systems that come out of the body control module (BCM) but not all functions where working. The system works by communication between the PCM or EEC what ever you want to call the computer under the hood. The BCM is under the back left seat attached to the rear fuse box. there is a data line that talks between the PCM and BCM and to know if the data lines are not compromised just look at your engine engine trouble light of the security dummy lights. If they are lit up you have good data going back and forth. In my car my security light was out and through prints and learning system on here my data lines where missing. the real easy way to know is plug in a ob2 reader if it says can not communicate with vehicle then you know your data lines have an issue. So now in my case I had to find the reason and if you have wiring diagrams which I am sure most of you don't the data lines not only feeds between the ECC and BCM (by the way that is where the security circuits are in)_but to all the door modules, lift gate modules window modules so the problem could be with any of those units. The problem is they are all over the car behind interior so you can imagine why this problem can cost much time to find. Since I was working on my own car now it didn't matter how long it took me to find it. for once I got lucky and I would suggest going to tail gate first because it is more likely to have the elements of rain and whatever to get to the boxes. As I opened my tail gate I hear my radio come on and said that is not right so first thing I did was remove the cover to the rear lock and window. It is the lower panel when you open lift gate it just snaps off. I unplugged my lift gate module and then all of a sudden all my systems began to work except the rear windows and roof window. I now had my dummy lights because the data was back and was being loaded down by the module I unplugged. I verified with my oscope which not many people have and seen the data now. I also plugged in my OB2 connector and now had communication to it. I still had a few systems broke but I had rang out the entire system for good grounds and power first and it was all there. I knew then that my BCM had been hurt when the latch gate module shorted. I bought one on line and replaced it and now all my systems started working but still not start signal. It took me some time to learn all this but found out you just can't take a bcm from another same type car because as soon as you do the key reset which is posted all over here by turning key to start then let go to run wait 10 min security light should go off (btw there is nowhere written I've seen that said you must wait the entire 10 minutes because that is how long it actually takes. Founds one video that showed this finally) turn off 10 seconds do it again. It says it can take up to 3 times to do this the video said 4 times) all was going good in the reset process until the 3rd time when after 10 min the security light came on solid and did not go out. when I tried to start What did happened is my radio got locked up and the security light would now go out. I was confused why if the security light is off it does not try to start? Here is why. Most people go on line or to a junk yard and get a replacement bcm the problem is that BCM was setup for the car it came out of. IF you took out the PCM and BCM out of the same car it would work this all part of there stupid anti theft system. Now you can order one on line or get just the bcm from a junk yard but here is where the dealers get you, the BCM needs reprogramming to match the PCM with the BCM. they can charge you about $150 bucks to do this but I figured since I would have to spend that I would by my own test equipment to reset and program my own for about $250 bucks. I can now have my own to repair and test other cars I will fix for anyone who can't get their car going. I am waiting on the test equipment and a new rear door module and I should be good to go. The system is junk because the electronics that send the data are not protected very well and any short in any system including jumping your cars battery can kill your car. Anyone of those modules hidden go bad can kill the system that is why it is so hard to find and there is no one fix for one car to the next. I'm surprised there has not been a class action lawsuit against GM for the trash they had put in. They know the system is so bad they tried 3 or 4 different systems and the passkey being the worst I believe. That is why you see aftermarket boxes to bypass the system. you see when you turn the key there is a hall effect circuit (fancy word for a magnet jn the key cylinder) which when the key is installed there is a 5 volt on a yellow wire under the top plastic cover of steering wheel. this is another problem I hear that the little plug that runs to the key cylinder intermittent and the signal get lost and locks you out to start. That is also very important always check that the 5 volt dc ref voltage is there because that is another reason it wont start. The best place to check all of that is take the top plastic cover off wheel and you will the a plug going to the key cylinder, it is a 3 wire plug. you should have 5 volts on the yellow wire with the key out and when you put the key in and turn it to on it should drop to a lower value(mine was 2.48 volts. Nowhere does it say what it exactly should be because I understand there are like 20 different PCM part numbers for the same envoy depending on options. I read where GM has about 10 different voltages the BCM is looking for so that is why you have to have BCM reprogrammed so key voltage and signal out matches the PCM. I short first check that you have an engine problem light (from PCM) or security light from the BCM that will tell you your data line most probably is working and not shorted. It can become loaded down as well but that is getting to deep. The other way to tell is if you hook up the OB2 reader (the little black plug to the computer located between your drivers side legs. you may have to get low to see it. If it works good and talks to computers its good. Next is the 5 volt reference volts. Sorry so long a text but this is such a big and vulnerable system that kills your great running car you can easily check these things. It was designed to keep your car from being stolen by either ripping out key cylinder or any tampering with wrong key. It actually turned out to be the owners worst nightmare. I will update after I get my new reprogramming tool din and the lift-gate module. I hope this helps you all because there is so much info all over its never fully explained so there you go.


btw it is never hardly the ignition switch but the wires that feed from it (3 wire plug I told you about) I told my mechs not to change it but they did anyway that is why I'm fixing it. I am not upset at mechs that could not find it. unless you work with that system it can be a mother to find.


also if you need a PCM or ECU whatever you want to call it it has to be reprogrammed by dealer as well. I suggest going to Flagship One who not only will sell you the ECU cheap but you give them vin number and they program exactly what your cars options are. I understand they are the only company that is licensed by GM and other manufactures. you can use an old one out of junkyard just remember it may not work because it is not programmed to the BCM.


BTW when you open the tail gate you will see at top a rubber boot that wires run through. My windshield wiper died in the back so when I removed the boot to check wires one was cut. I have heard up to 3 wires getting cut because of how the wires are run. It takes a second to pull boot back and pull out wires there is a plug in there (have to pull wires to see) if all looks good you maybe ok it just another big issue with GM


update. I was questioning if that lift gate module could have caused the data loss because I opened unit and it looked pretty good no burn marks but it still could have been. I told you all about at the back of the tailgate the rubber tubing the wires run through from the vehicle to the door. a year ago my wiper stopped working and I found the black wire was cut and could not figure out how that happened but spliced and all was good after that. I went back today to double check that circuit power and grounds to make sure that did not cause the problem. there are 3 connectors on the module under the tailgate cover so I went back and found now no power on pin A large orange wire and no ground as well. As soon as I seen that I opened back where I had repaired the wire before to see if there? what I found was the orange and black wire where partially cut as well but when I fixed the ground wire a year ago the other 2 wires where half way cut and as we opened the tailgate to get food out or whatever it slowly bent partially cut wires I did not see further back and they finally opened. when I removed the wires from the module and my data came back I assumed it was that and with other problems to look at I went back to verify and low and behold they were both on by a few strands of wire. enough to ring correct and see voltage but not enough strands to hold the current it needed to operate. you really have to pull on the black and small and large orange wire because the wire covering was holding it together and as soon as I pulled on one it came apart same as the other. So Now I believe when that happened for some reason the tailgate module loaded down the data signal which when I unplugged I got data back but the real problem was the wires going through the vehicle, It should have shorted and blew the fuse but it has a 30 amp fuse and with the wires strands broken it opened the wires first before the fuse, they had less resistance. I have seen all kinds of problems on line that could be because all the modules run to the data lines and anyone could have done it. I am now waiting on the X100 programmable test equipment to come and reset my key and security system and hopeful it will start. I can not believe a simple short in a door circuit could lead to killing my BCM (I changed my original because only so many outputs worked and now they all work so all is need is to reprogram. I hope all this will help somebody else save a car that is perfectly healty and good yet a security system fault can down your whole car. If it was an easy fix I am sure the other 2 shops that worked on mine would have found it but it really is unbelievable that it happened at all.

I worked on a 06 gmc envoy Denali with a crank no start. Only dies after car warms up and runs for a bit so lead me to believe it was something electrical I started testing all components that check engine light gave codes for and all were good harness was also good. Used relay tester and found the relay kept loosing it's ground at the fuse box so opens up fuse box and found a broken copper wire used inside of the fuse box replaced with a new solid copper wire 20 gauge wire btw. Made sure there was no otheres then put everything back on and problem was fixed after that hope this helps yall out

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