EUREKA! I figured it out.
The issue is the 3.3 volts the CH341a programmer puts out. It's not enough. I reworked the CH341 programmer to output 5v to the chip, and it read right off the board. No need to desolder the chip at all. Just clip on and it reads. The voltage rework is here:
next issue was with TachoSoft. The version I downloaded (free, and probably pirated) did not have a 2007 Cobalt. only 2004-2005, and then another for 2006. However, you'll notice there is a pattern. on lines 3B0 and 3C0, there are some characters that repeat 3 times. All the other cobalts listed the same characters, so I just assumed 2007 was the same, and it was. Tachosoft was in kilometers, so I had to do that calc to miles, and it spit out a set of hexdata to change.
My car now has 5367 miles on it, which is a 5000 mile motor when I bought the car (new long block), plus the miles I've put on it since the build. It's approximate, but it's much closer than the 136k miles it showed before.
The issue is the 3.3 volts the CH341a programmer puts out. It's not enough. I reworked the CH341 programmer to output 5v to the chip, and it read right off the board. No need to desolder the chip at all. Just clip on and it reads. The voltage rework is here:
next issue was with TachoSoft. The version I downloaded (free, and probably pirated) did not have a 2007 Cobalt. only 2004-2005, and then another for 2006. However, you'll notice there is a pattern. on lines 3B0 and 3C0, there are some characters that repeat 3 times. All the other cobalts listed the same characters, so I just assumed 2007 was the same, and it was. Tachosoft was in kilometers, so I had to do that calc to miles, and it spit out a set of hexdata to change.
My car now has 5367 miles on it, which is a 5000 mile motor when I bought the car (new long block), plus the miles I've put on it since the build. It's approximate, but it's much closer than the 136k miles it showed before.
