Hardware Test error "4SNS/1/40000000:Th1H-84.500"?

Apple Hardware Test v3A173 extended run reported error "4SNS/1/40000000:Th1H-84.500" (runtime 1h10m)?

System:

MPB, Intel Core 2 Duo 2.26Ghz

2 x 2GB 1067 MHz DDR3s

OSX 10.5.8

Symptoms:

On every startup, I get Date & Time warnings about being reset prior to 2001. When I attempt to connect to my wireless network to auto-correct it, I am prompted for my password, despite the fact that all of my 'remembered networks' still exist under Network Settings>Advanced.

What started this whole debacle:

The battery was allowed to drain completely completely?

What I've done:

After quick research I suspected an NVRAM issue, so I performed the reset on bootup, connected to WLAN for auto-correct, restarted, but no luck.

I brought it into a Genius, and he thought to try SMC reset (I think he may have done both?), but no luck. He ran their hardware test, battery failed (the red X icon) so he put a fresh one in the machine, confirmed it passed hardware test, booted up, manual date/time correction and all and restart, but no luck.

At this point we suspected a problem with my OS installation(?), so we bootup through one of their externals with the closest OS version (don't know what he used), and the date is not reset. He recommended an Archive & Install OS X from disc. There were some Disk Utility checks in there somewhere too but everything checked out.

So I went home and performed Archive & Install, set the date and restart, but still no luck (now I am 10.5.7). Next step was going to be a full Erase & Install from disc, but I decided to run a Hardware Test from disc instead. I'm going to run a Software Update and go to bed. 😟