Broken Car Key: Repair or Replace?

A snapped or worn car key can sometimes be repaired, but only if the chip inside is undamaged and the failure is mechanical (a cracked blade or a shell that has worn through). If the chip has been crushed, corroded or is electronically dead, repair is not an option and the key has to be replaced outright. The deciding factor is always the chip, not how bad the plastic looks.

What "repair" actually means on a car key

Chris here, and this is one of the most misunderstood jobs in the auto side of the trade. Drivers assume a locksmith can weld a snapped blade back together like a normal front-door key. They cannot, not reliably, and any repair that tries to rejoin a broken blade is a false economy because the metal has already fatigued at the break point and it will let go again, usually at the worst moment.

What actually happens in a genuine repair job is a re-shell: the working transponder chip and any remote buttons are extracted from the damaged housing and transplanted into a new key shell and blade blank. The electronics that talk to your immobiliser never get touched. That is the entire trick, and it is why chip condition decides everything.

When a repair or re-shell is genuinely viable

From the jobs we see across the Adelaide network, re-shelling is a clean, cheaper fix in a specific set of situations:

• Snapped blade, intact head: the plastic head housing the chip and buttons is undamaged, only the metal blade has sheared off.
• Worn-out shell: the plastic case has split or the buttons have stopped registering, but the key still starts the car when the blade is used or the remote is pressed close to the ignition.
• Chip still reads: the locksmith can test the transponder with a diagnostic tool before committing to any work, so you are not paying to find out.

If your key still starts the car at all right now, even roughly, even with a wiggle, that is usually a good sign the chip is alive and a re-shell is on the table.

When replacement is the only path

Some damage takes the decision out of your hands. Replacement is the only realistic option when:

• The key has stopped starting the car entirely, which usually points to a dead or damaged chip rather than a mechanical fault.
• The break happened inside the ignition barrel and part of the blade is still lodged in the lock. That is a two-part job: extraction, then a fresh key.
• Water or corrosion has reached the circuit board inside the fob, which is common with keys that have been through a wash cycle or left in a wet pocket.
• It is a smart proximity key with internal battery and antenna damage, where the cost of diagnosing and repairing the board approaches or exceeds a straight replacement anyway.

In every one of these cases, spending money trying to save the old key just delays the inevitable replacement bill, so it is worth being upfront about it rather than chasing a fix that will not hold.

Repair vs replace: typical Adelaide cost comparison

Where a repair is genuinely possible, it is almost always the cheaper route, because you are only paying for the shell, blade and labour, not a fresh transponder that needs programming to your immobiliser from scratch.

These are typical Adelaide ranges, and your quote may differ depending on make, year and whether the immobiliser needs to be reprogrammed. A re-shell sits at the bottom of the scale because it skips the programming step entirely, the chip already knows your car.

How to decide before you call anyone out

A quick self-check before booking a locksmith: does the key still start the car, even awkwardly? Is the damage limited to the plastic shell or the metal blade, rather than anything electronic? If yes to both, mention that clearly when you request quotes, because it changes what the locksmith brings to the job and can save you a second call-out. If the key is completely dead or the damage involves water, a snapped blade stuck in the barrel, or a smart key that will not wake up at all, budget for a replacement from the start.

Either way, a mobile auto locksmith can usually test the chip on the spot and tell you within minutes which path applies to your key, rather than guessing over the phone. For a tailored estimate on a full replacement, the car key replacement cost estimator gives a ballpark based on your make, year and key type before you commit.

If you are weighing up whether to fix your current key at all, it is worth reading how the numbers stack up for a full car key replacement in Adelaide, and if you are only after a backup rather than fixing a broken one, see what a spare car key typically costs while your original is still working.