Hypertech tune = truck will not start!

[txperformance]

I have been a member of this forum for a long time now but this is my first post. I have learned a LOT of valuable info from this site on previous builds and i hope to get some insight or suggestions with a problem im having right now.

I have an '01 Yukon Denali 6.0 pretty much all stock programmed w/ Hypertech PP3 and it's been running great for over a year. A couple days ago I hooked up the programmer to adjust my tire size and now the truck wont start.. it cranks and runs for a second then seems like the ecm shuts off fuel. Please note I have had Passlock issues in the past but i bypassed it about a year ago and ive had zero issues since. I would otherwise diagnose this as being a VATS issue but the security light is NOT illuminated, not blinking or anything with the key on. It only blinks with the door opened and turns off when the key is turned on. I've tried everything, unhooked the battery, reprogrammed to stock, tried a security relearn 3 times and nothing is working. I did not have any trouble codes when i scanned it either... Im thinking the ecm might be screwed up because the truck was running absolutely perfect before i parked it and hooked up the programmer. I been wanting to get the passlock and on-star deleted from the computer anyways (if that's possible) and get custom tune. Is it worth it to invest in HP Tuners? Should I send the ecm off to a professional tuner or should I just get a dealer re-flash? Im very good with electrical & wiring and im usually pretty good at figuring these things out with the help of forums and such but this issue has me stumped... Any help would be greatly appreciated!

P.S. i also called Hypertech and they basically told me the tuner is "outdated" and there is nothing they can do or recommend for me, but they insisted it is not an issue with the program! Even though the truck was running great before i plugged it in...

 

[ezdaar]

Remove the tune, see if it runs... would seem logical.

 

[Ben]

you got the wrong tune.

 

[txperformance]

I've already removed the tune & put everything back to factory specs... that was the first thing i tried. It did not work.

---------- Post added at 08:59 AM ---------- Previous post was at 08:11 AM ----------

Whats confusing me is I tuned the truck with the exact same programmer a little over a year ago and have been running the tune with zero issues until i tried to change the tire size...

 

[Ben]

remove the battery for 30 mins

 

[txperformance]

remove the battery for 30 mins

I tried that also, i removed both battery cables for about 6-8 hours, hooked them back up and still no start...

 

[Yukon&Tahoe]

Or at least disconnect the battery for the 30 minutes..... memory should be lost/reset, re-install battery connections and give it a try?!

 

[Screwd up 6]

Sounds like the security relearn. Mine did this when I bought a custom tune.

To do the security relearn:

1.) Attempt to start the car by turning the key to the Start/Run Position.

2.) Observe that the vehicle fails to start and that the security light is illuminated.

3.) Release key to the 'ON/Accessory' Position. (DO NOT turn key to the 'OFF' position).

4.) Allow the vehicle to sit with the key in the 'ON/Accessory' Position for at least 10 minutes until the security light turns off. (turn off lights/radio/etc to save battery)

5.) Turn key to 'OFF' position and remove key. Allow the vehicle to remain in the 'OFF' position for at least 45 seconds.

6.) Repeat steps 1-5 for 3 cycles.

7.) On 4th attempt, your car should now start.


***STEP 3 IS IMPORTANT TO NOT TURN THE KEY TO OFF POSITION***

 

[txperformance]

Sounds like the security relearn. Mine did this when I bought a custom tune.

To do the security relearn:

1.) Attempt to start the car by turning the key to the Start/Run Position.

2.) Observe that the vehicle fails to start and that the security light is illuminated.

3.) Release key to the 'ON/Accessory' Position. (DO NOT turn key to the 'OFF' position).

4.) Allow the vehicle to sit with the key in the 'ON/Accessory' Position for at least 10 minutes until the security light turns off. (turn off lights/radio/etc to save battery)

5.) Turn key to 'OFF' position and remove key. Allow the vehicle to remain in the 'OFF' position for at least 45 seconds.

6.) Repeat steps 1-5 for 3 cycles.

7.) On 4th attempt, your car should now start.


***STEP 3 IS IMPORTANT TO NOT TURN THE KEY TO OFF POSITION***

I've had to do security relearn a couple of times in the past and it worked great for me then, but this time is different... My security light is NOT illuminated or blinking when i attempt the re-learn process. I even attempted a re-learn just by timing the key cycles (10 mins on 30 secs off X3) despite not having the security light and it's still not working... Thats what leads me to believe my computer might be fried...

 

[JennaBear]

There are a few threads like this on GMFS, for both the Hypertech and the Bullydog handhelds. Unfortunately, from the threads I have seen, it was not a security relearn issue, the handhelds had fried the PCM, and a new one had to be purchased at the dealer.