So here I would like to share my experience disabling F55 and reflashing DBS using GM Tech2 scan tool . I have a 2005 c5 F55 with heads, cam, injectors, etc. tuned with HP tuners. I did some search about having the DBS reflash and F55 disable done and I read in a couple blogs and threads that people are unsure whether the DBS reflash or any other BCM changes will affect custom ECU tunes. I had the tech do these two changes to the BCM and checked the car after each.
Tech 2 for GM is Professional GM Diagnostic Scan Tool. GM Tech2 scanner supports all GM systems from 1992 to 2011.Tech2 has powerful function which make it is first choose by most GM vehicles repairer.
Disclaimer: Please strictly follow the steps in case anything goes wrong. The F55 disabling and DBS reflashing are on your own risk.
First I had the tech do the DBS reflash for me in about 10 min. My tune was NOT affected and the car started and ran normally.
I then had him disable the F55 suspension. Again, my tune was NOT affected and the car started and ran normally.
It is also worth noting that HP Tuners can NOT make changes to the BCM.
If you are looking to disable your F55 using the TECH2 scanner :
1. Hook up Tech2 , turn car ON, make sure module in the rear is PLUGGED IN. Do Not unplug the rear module.
2. Go to diagnostics — Body — BCM — BCM Special functions — BCM Setup.
3. Delete the F45 option ( F55 did not appear on the menu screen on the Tech 2, use F45)
4. Save new configuration.
5. Do not turn car off, Car Diagnostic Tool do not remove Tech 2, go to the module in the rear of the car, unplug the grey connector( the widest one) leave the center plug in and the smaller black plug in.
6. Turn off car leave Tech 2 plugged in.
7. Remove remaining plugs from module in the rear of car.
8. Turn car on to verify the “Max speed 80 mph” is gone.
9. Unplug Tech 2 and put tools away.
Then you have to follow the bouncing ball of checking off RPO Codes. When you get to F55 set it to disabled.