2008 Tahoe runs and then shuts off

[Rpenajr4]

I don’t know if anyone has had this issue, but my Tahoe runs for like 20 minutes shuts off, I remove the key off the ignition wait for a couple of minutes or I remove the relays re-insert them and the truck fires up like nothing and then repeats shuts off and I do the exact same thing over and over. I have checked the wire harness from the fuse/relay box no wires broken. I’m at a loss don’t know what else to do has anyone experienced this issue in the past?

 

[Fless]

Why do you remove the relays, and which ones are you pulling?

 

[Rpenajr4]

Why do you remove the relays, and which ones are you pulling?

I pull the run/crank and pwr/trn relays hear the relay click then the truck starts right away for another 10 min or so and shuts off again and I have to repeat the process.

 

[strutaeng]

Can you swap out the relay to see if that's the problem?

 

[alpha_omega]

Have you hooked up a scan tool to see what’s going on? Tested the alternator and battery?
Maybe the alternator is dying and the battery isn’t getting enough juice to keep it running? That doesn’t make sense though, because it wouldn’t fire back up.
Does it die on you if the vehicle is in park or you’re driving? Not saying you want to get stranded somewhere, just trying to get an idea for what’s taking place.

 

[Rpenajr4]

Have you hooked up a scan tool to see what’s going on? Tested the alternator and battery?
Maybe the alternator is dying and the battery isn’t getting enough juice to keep it running? That doesn’t make sense though, because it wouldn’t fire back up.
Does it die on you if the vehicle is in park or you’re driving? Not saying you want to get stranded somewhere, just trying to get an idea for what’s taking place.

Alternator is new, replaced it when the battery light came on dash. codes present are the down stream O2 sensors. Truck shuts off while sitting at idle or running. I either wait like 5 minutes or unplug the relays hear them de-energize and the truck fires up like nothing but only gives me a 15-20 minute run time.

 

[kbuskill]

Alternator is new, replaced it when the battery light came on dash. codes present are the down stream O2 sensors. Truck shuts off while sitting at idle or running. I either wait like 5 minutes or unplug the relays hear them de-energize and the truck fires up like nothing but only gives me a 15-20 minute run time.

What does the truck do if you don't pull the relays and just try to start it?

Does the starter engage and spin the engine, or does it not function at all?

 

[mikez71]

Can you swap out the relay to see if that's the problem?

x2, I would try a different relay, especially the run/crank.

 

[rdezs]

I would focus on one item at a time when it dies. Pull the run crank relay as you've been doing but nothing else, then insert it again. If it starts and days in 20 minutes again.... I would think it's safe to assume the relay is defective and replace it.

That 20 minute window of running is a definite clue, and the only thing that comes to mind for me is that a relay is overheating at about that time consistently. If you're below a quarter tank of fuel, fuel pumps are known to overheat and start having issues... But the consistent 20 minute time frame wouldn't fit. (It would change with your fuel level as the fuel cools the fuel pump)

Once you've identified the problem, I would replace all relays if they look like they're the originals. They do wear out over time.

 

[alpha_omega]

I would focus on one item at a time when it dies. Pull the run crank relay as you've been doing but nothing else, then insert it again. If it starts and days in 20 minutes again.... I would think it's safe to assume the relay is defective and replace it.

That 20 minute window of running is a definite clue, and the only thing that comes to mind for me is that a relay is overheating at about that time consistently. If you're below a quarter tank of fuel, fuel pumps are known to overheat and start having issues... But the consistent 20 minute time frame wouldn't fit. (It would change with your fuel level as the fuel cools the fuel pump)

Once you've identified the problem, I would replace all relays if they look like they're the originals. They do wear out over time.

x2 on what these guys said.

Has this vehicle been outside parked for any length of time? Not used over winter or Sat for a month before being purchased or while I drove my other vehicle?

I only ask that because in addition to the relay going bad, there could be something under the fuse box (underhood) that is causing the relay to heat up. Bugs like to crawl up there and die, mice love eating and leaving debris under there as well. Not saying that’s the cause, but it could also be adding to the problem.


One step at a time though.

 

[Rpenajr4]

What does the truck do if you don't pull the relays and just try to start it?

Does the starter engage and spin the engine, or does it not function at all?

No, the lights on the dash light up but there’s no starter engagement, not even an engine bump or click nothing. Lights do dim as if the truck wants to start but nothing, I did replace my starter with an oem new not rebuilt thinking that was the problem since the alternator and battery were replaced.

 

[Rpenajr4]

x2 on what these guys said.

Has this vehicle been outside parked for any length of time? Not used over winter or Sat for a month before being purchased or while I drove my other vehicle?

I only ask that because in addition to the relay going bad, there could be something under the fuse box (underhood) that is causing the relay to heat up. Bugs like to crawl up there and die, mice love eating and leaving debris under there as well. Not saying that’s the cause, but it could also be adding to the problem.


One step at a time though.

I removed the fuse block to make sure the connector pins were not corroded or even the wires broken, they weren’t, I clean everything underneath as well since I was already there l. As far as the truck service time it’s my work daily and as far as the fuel I always have it above half a tank. I have removed one of the two said relays at a time and it doesn’t start unless I unplug both. I have a 13 Silverado and used its relays since they are the same relays and still did the same thing. I was going to use the fuse block from my Silverado since they look identical but there was one pin off so I didn’t.

 

[alpha_omega]

So if you remove the other relay still only removing just one, do you have the same issue?

And you swapped both relays with one from the Silverado? Still 10min shut down?

You fully removed the fuse box and checked underneath it? Blowing it out with air and making sure all the pins are good, no loose wires on those relays you’ve removed?

 

[Rpenajr4]

So if you remove the other relay still only removing just one, do you have the same issue?

And you swapped both relays with one from the Silverado? Still 10min shut down?

You fully removed the fuse box and checked underneath it? Blowing it out with air and making sure all the pins are good, no loose wires on those relays you’ve removed?

That is correct, I used the relays from my Silverado still did the same issue. I removed the fuse block made sure there was no corrosion on the pins cleaned the connectors still same issue.

 

[alpha_omega]

Anybody you know have a scanner?

 

[rdezs]

Look up what GM refers to as the "extended parking feature" that's supposed to automatically shut off the engine that exactly the 20-minute mark if it thinks the vehicle is parked. Not sure what year they started doing that, but it sure sounds like it. If that's the case, I would suspect the switch on the driver side of the transmission, which detects every gear that you are in... And communicates that to the ECM.

Racking my brain, that's all I got with a 20-minute symptom.....

 

[Rpenajr4]

Look up what GM refers to as the "extended parking feature" that's supposed to automatically shut off the engine that exactly the 20-minute mark if it thinks the vehicle is parked. Not sure what year they started doing that, but it sure sounds like it. If that's the case, I would suspect the switch on the driver side of the transmission, which detects every gear that you are in... And communicates that to the ECM.

Racking my brain, that's all I got with a 20-minute symptom.....

Drove it today for work, it was hot as hell around 106, truck turned off on me within 5 minutes this time waited like 2 minutes came back on made it to work? I’ll make sure to check that switch if it’s equipped.

 

[Rpenajr4]

Look up what GM refers to as the "extended parking feature" that's supposed to automatically shut off the engine that exactly the 20-minute mark if it thinks the vehicle is parked. Not sure what year they started doing that, but it sure sounds like it. If that's the case, I would suspect the switch on the driver side of the transmission, which detects every gear that you are in... And communicates that to the ECM.

Racking my brain, that's all I got with a 20-minute symptom.....

Went to work yesterday at 6:00 pm its was hot like the devils butthole, truck lasted 6 minutes, waited for 3-4 minutes turned on and was able to make it to work.

 

[mikez71]

Did you have to pull the relays that last time?
If it shuts down, and you pull/reinsert the relays, do you still have to wait to start it?

I wonder if the fuse box is bad, since you are getting the signal to crank if your lights dim.. ?

 

[Matahoe]

Drove it today for work, it was hot as hell around 106, truck turned off on me within 5 minutes this time waited like 2 minutes came back on made it to work? I’ll make sure to check that switch if it’s equipped.

Looks like an open circuit somewhere. The heat expands connections leaving a gap. My guess is you have a remote start bypass that has a loose connection. Does the truck have anything like that?