Reading Initial Tune While Vehicle is Partially Disassembled

[marasjm5]

I'm currently in the process of a frame swap with an engine and transmission rebuild on my 2011 silverado. I read that it is important to read, resolve, and clear DTCs prior to reading a tune. Having obtained my mpvi3 and studied how to use HPtuners in the middle of this job, I never got to read a stock tune prior to disassembly. Fast forward some time, and the truck is 93% finished today. I'm waiting on my exhaust and I have some minor things to wrap up. The truck is overall ready for a key on engine off. Considering that I'm waiting on my exhaust, I have some free time to start adjusting a tune for the truck. Having no 02 sensors at the moment, an unpinned vvt harness, afm delete, etc. I'm sure it's bound to set a DTC at key on. I imagine the reason to resolve DTCs is to fix a driveability issue which affects engine operation prior to tuning? Can anybody confirm this? The overall question is; Am I able to safely read a tune with a handful of incomplete circuits, such as MAF and 02 sensors, etc? I will not be writing the tune onto the vehicle until the vehicle is complete.

[gtstorey]

Never heard anything about fixing codes prior to reading the tune. But you do need to turn off some codes in the tune prior to them setting as "permanent" codes. Post in the GM Gen4 V8 section for more help.

[marasjm5]

Thanks for the quick reply. In the HPtuners website it states: "When you begin tuning a new vehicle, ALWAYS check the vehicle for diagnostic trouble codes (DTCs) and resolve as many as you can before you do anything else. If there is a mechanical issue with the vehicle, it may affect performance and any performance data you want to monitor could be impacted. This makes it very difficult to tune the vehicle effectively." This is where my concern came from. I figured that statement was directed towards resolving runability issues prior to tuning for accurate results. This being my second vehicle that I will be tuning, (the first being a complete vehicle with zero DTCs) I wanted to confirm prior to reading the Silverado. I appreciate your time.

[gtstorey]

You don't want to attempt to tune a vehicle with "real" codes that indicate a mechanical or electrical problem. Not really directed at "reading" the vehicle since the read is static. But the concern of setting a permanent code at key on is real if the vehicle will be inspected. I don't know if the permanent code can set on key on or if it actually has to start for them to be permanent. But once a code is set as permanent it will have to actually pass the test to clear and can't for removed equipment. I think this applies to your truck, but posting in the correct forum will get the more knowledgeable people to possibly weigh in.