Hi all. My wife and I struggled with intermittent air bag code 22 for several years. The short story is the cause was the driver's seat side bolster air bag itself. Replaced with a $200 used airbag and the light is off and the problem is gone. It was diagnosed checking the resistance (ohms) in the circuitry. The first shop thought it was a poor connector under the seat and repaired it with a butt splice. That worked for a year, followed by a couple years of frustrating intermittent code 22. The second shop also thought the butt connection was the issue and replaced it. That lasted about a month.
Here are the electrical values that led to replacement and confirmation. Circuit resistance with original splice repair 3.8 to 4.0 ohms. After second splice repair 2.8 - 3.0 ohms. Eventually the light came back on. They compared the value with the passenger side reading which led to replacing the driver's bolster air bag. Now both seats' circuitry shows 2.4 ohms, which apparently is what it should be. We're impressed with the shop that found the solution; English Auto in Odenton, MD.