Occasionally, with either key fob inserted into the dash, the start button has no effect. Ejecting, re-inserting and repeating the procedure, sometimes three or four times, wakes things up and the car starts instantly.

Bad fob "switch" in the dash? I've watched a video on how to remove the unit but what is needed to program a replacement?

Thanks,

Erwin
2008 V70 65,000 miles.

When you insert the key, do the dash lights come on? Any messages in the message center? Have you tried using the remote to lock/unlock the car 5 times?

Check the battery negative and make sure it is clean. If you have a mirror, check the wire connectors at the starter, looking for corrosion.
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Keeping it running is better than buying new

Battery terminals are clean. Instrument lights come on but warning lights when pushing button and it's going to start. No messages. Have not tried the 5 lock-unlock cycles. It hasn't happened today through a dozen starts. To answer James question, yes I jiggle the brake pedal but that's not conclusive.

Have you tried fiddling with the brake pedal instead of the key when the problem arises?

I only mention this because a switch on the brake pedal would be far easier to fix.