A fob that worked yesterday and not today usually has a simple cause. Consequently it is worth five minutes of checking before assuming it needs replacing, because replacement is the expensive answer to a cheap problem.
Rule out the battery
Start here, because it is the answer most often. A fob battery lasts roughly two to four years, and cold shortens it. Consequently Ottawa fobs fail more often in January than July. Moreover most fobs open with a coin or a small screwdriver, and the cell costs a couple of dollars.
Try the spare
If the spare works, the car is fine and the fob is not. By contrast, if neither works, the problem is in the vehicle. Therefore this single test tells you which half to investigate. Additionally it is free and takes thirty seconds.
Get into the car regardless
Almost every fob contains a mechanical emergency key. Furthermore, most vehicles hide a keyhole under a plastic cap on the driver's door handle. Consequently a dead fob is not a lockout. However, expect the alarm to sound until the car recognises the fob, which is normal rather than a fault.
When it needs programming
Fobs occasionally lose their pairing after a battery disconnection or a low-voltage event. Consequently reprogramming restores them without new hardware. However, water damage and physical failure are different, and no amount of programming fixes those. Therefore we test the fob before selling you a replacement.
Questions we get about this
How long does a fob battery last?
Two to four years. However, cold shortens it, so Ottawa fobs fail more in winter.
Can I change the battery myself?
Usually, with a coin or small screwdriver. Consequently it is worth trying first.
How do I unlock the car with a dead fob?
Use the hidden blade in the fob and the keyhole under the door handle cap.
Will the alarm go off?
Often, until the car recognises the fob. That is normal.
Can a fob be reprogrammed rather than replaced?
Frequently yes, if the electronics are sound.
