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2006 gmc envoy_sle_xl
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Discussion Starter · #1 ·
Hi all. As mentioned I have a 06 Denali. I'm having a bugger of a time. Car cranks excellent but won't start. Here's the story. Been having intermittent starting problems,thought it was fuel pump as it was original with 137000 miles. Replaced ,car started fine and ran excellent but ultimately died. Left it for 24 hours and went to trailer it home,get to truck,starts fine and put on trailer as I didn't trust it to drive across town. Was throwing code po443,replaced surge valve which after said and done was faulty,could blow thru it unhooked. It then threw code p1682 which I understand to mean ignition switch in most instances. Vehicle started fine next morning so I pulled it into the shop,shut off,and tried to restart,wouldn't start. Replaced ignition switch,still wouldn't start. Put in old switch it fired right up so got another switch and installed. Fired right up,left it running for 20 minutes or so,it died all on its own and wouldn't refire.It threw some new codes mainly to do with throttle body actuator but also the same code p1682. Any one have any insight? To recap-when cold and first start it fires right up,when warm it won't.
 

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2004 chevy trailblazer_lt
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1,040 Posts
The first thing I would do is check the fuses in the underhood fuse box to make sure they are seated properly. The second thing I would do is to switch the fuel pump relay with the A/C relay. Sometimes when the fuel pump relay gets hot, it opens up rather than staying closed causing a no start situation.

Good Luck!
 

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2002 chevy trailblazer_lt
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code p1682 which I understand to mean ignition switch in most instances.
I think the P1682 specifically means an imbalance between 2 circuit voltages... The ignition switch could be a common cause but not the only possibility. Poor connections or damaged wiring I would say are a more common cause for any intermittent condition. There are 2 power supplies and 5 loads handled by the ignition switch. Checking the voltages seen at all 7 terminals of the switch at the RUN and CRANK positions might help.
Screenshot_20210313-081917.png




Have you examined your powertrain relay and related fuses & wiring?

Screenshot_20210313-080004.png
 

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2006 gmc envoy_sle_xl
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Discussion Starter · #4 ·
thanks for the replies guys. I went out this morning and car started right up. Pulled and cleaned all fuses and relays in distribution box under hood. again car started right up but died after 20 minutes. closed up things and took the rest of the day off, just getting frustrated. My good buddy was a GM certified master mechanic that retired after an accident at work and sold his top end scanner so I don't have that capability. When I replaced the ignition switch the original had one of the teeth busted off,no idea where the tooth ended up. It just baffles me that it dies after warm up. At first start up it runs immaculate,revs great. I'm not great at tracing electrical problems and reading schematics. Thanks for listening.
 

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2005 gmc envoy_denali
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5 Posts
The fuse box under the hood may have a cracked trace that separates after it heats up and will cause the engine to stall and not start again for a couple of hours. I've had this happen to my 2005 Denali. You can either find the bad trace and repair it or replace the fuse box. I found a new fuse box on ebay and replaced mine and I haven't had any issues for about a year now.
 

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2006 Chevrolet Trailblazer LS
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40 Posts
Excuse my ignorance but what is a bad trace?
A crack or break on a circuit board. Heat will cause them to separate.
Also, when inspecting circuit boards, look closely for bad solder connections - they should all be bright and shiny and very consistent since they were done by machine (unless someone repaired later, in which case, inspect very closely).
Don't be worried about being a little rough - if they break, you found an issue!
 

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2004 chevy trailblazer_lt
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A trace is the copper/conductive foil on a circuit board. In this case, think of the fuse panel as a large circuit board. The traces run from the fuse sockets to one of connectors that a cable bundle connects to.via a mating plug.
 
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2005 gmc envoy_slt
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okay great,thanks for the info guys.I'll see what I can find tomorrow.
If i was you,I'd disconnect the fan clutch plug, start it until it dies,squirt starting fluid to see if you have you have spark-compression. if it tries start,then you have a sensor issues--maybe temp sensor,maybe coolant level sensor.-since it seems to run fine when its cold.--maybe when its running get to a place that can read your codes-code readers help,alot.
 

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2006 gmc envoy_sle_xl
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Discussion Starter · #13 ·
Well it took a couple of weeks due to my schedule at work but I finally got it figured out,I hope. Replaced fuse box with used one from junk yard and everything has been running great. I hope that I didn't just temporarily fix the problem with a used part that is gonna go bad also,the donor vehicle had almost 300,000 miles while mine has 140,000. New ones are hard to find but if anyone needs one go to autopartscheaper.com,it jumps to conquest auto parts but they do have one available priced at 280.00 plus shipping. Thanks for the assist.
 

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2002 chevy trailblazer_lt
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anyone needs one go to autopartscheaper.com,it jumps to conquest auto parts but they do have one available priced at 280.00 plus shipping.
Damn!! Next trip to the yard I think I'll grab a couple. About $20 there.
 
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