Disconnecting the battery and removing air bag fuses is a standard part of almost every procedure. It is usually not necessary but is included for liability reasons. If you do something to pop an air bag and get hurt, the lawyers can say "you didn't follow procedure".
In reality, you have to work pretty hard to pop an air bag. I've replaced a lot of clock spring assemblies and done other repairs that required removing the air bag from the steering wheel, and I never disconnected the battery. Now the manufacturers have added another insane problem. Disconnecting the battery or running it dead can leave the car with a no-start condition, or if it does start, it won't come out of park and the engine speed won't increase when you press the gas pedal. The car has to be dragged skidding onto a flatbed truck and hauled to the dealer to have them unlock various computers. Only Volkswagen is worse than GM in that respect, but many GM cars will still start and run okay as long as no computers are replaced. That didn't start affecting GM cars until somewhere around the mid 2000s. For Volkswagens, that goes back to the early '90s. It's one of the many reasons I will never buy another new car.
Here's what I copied from a similar post:
Try the 30 minute relearn sequence.
30 Minute Re-Learn Procedure
1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON (vehicle will not start).
3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes ( the vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK).
The vehicle learns the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
6. Start the engine (the vehicle has now learned the Passlock Sensor Data Code and/or password).
7. With a scan tool, clear any DTCs if desired (history DTCs will self clear after 100 ignition cycles).
Saturday, January 14th, 2012 AT 5:54 AM