2005 tahoe P0480 help

[Troy272]

I have a 2005 Tahoe 5.3 with 248,000 miles. On Monday morning I noticed that the cooling fan was running even though I hadn’t started the truck yet. Since then, the cooling fan will run after I turn the vehicle off. What’s odd is sometimes it won’t do it until an hour or 2 after it’s been off. Also my temperature gauge is fine, no overheating.

I did a code scan and P0480 comes up. I replaced the relay for cooling fan 1 and no change. I decided to disconnect the battery, cleaned the 2 huge harnesses that go to the PCM, and cleaned the connectors to the fan control fuse block (not sure if that’s the correct term sorry). I even removed and cleaned the connectors to the cooling fans and still no change. Could it be a grounding issue? I think I found the ground connector (passenger side radiator support area) but will have to put the truck on ramps to get a better look and grip on it. I’m kind of lost at this point and was wondering if anyone could help.