Lennox Furnace Won't Open Gas Valve

I have a 3 year old Lennox ML 180UH with control board 103085-02. I've spent the last 5 hours diagnosing why it won't light, and everything checks out fine until you get to the gas valve opening - voltage goes from 0 to maybe 2v at the most before the furnace kicks off and restarts the cycle. I have verified the following:

1. Pressure Limit Switch is good and hose isn't clogged
2. Igniter resistance and voltage are sufficient, it glows white hot
3. Ventilation/exhaust is good
4. Gas is on (I have two furnaces and the other works fine)
5. Thermostat is not the issue (tried swapping the two and it didn't fix it)
6. Rollout switches have continuity
7. Flame sensor is clean; the gas never flows, there's no click from the valve opening and the flame never lights

Any idea why when the signal gets sent to the gas valve to open it doesn't work? I'm guessing the board is the problem but I don't want to order one and wait 2 days to find out that's not the problem.

submitted by /u/magnus87
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