Question 1

Do you use OEM or aftermarket keys on a 2012 Subaru Forester?

Accepted Answer

For this generation, a quality aftermarket transponder key blank with the correct chip spec programs reliably and works exactly like the original. The 2012 Forester is not the kind of vehicle that rejects non-dealer keys the way some newer systems do. What matters is that the chip type in the blank is correct for this immobilizer and the key blade is cut accurately to your specific vehicle. We use verified blanks, not whatever random lot came in cheapest. The shell, the blade, and the chip all have to match. When they do, the car does not know or care who made the blank.

Question 2

How long will a replacement key last on one of these?

Accepted Answer

A long time, realistically. The transponder chip inside the key head has no battery, no moving parts, and no expiration on the programming. It's passive, meaning it draws power from the antenna ring around the ignition cylinder when you insert the key. The part that wears is the physical key blade and the plastic head. If the head cracks or the blade gets bent from being used as a bottle opener, the fix is a new blank and a fresh cut, not a whole new programming job in most cases. Use a quality keychain that doesn't torque the blade sideways in the ignition and this key will likely outlast the car.

Question 3

What if my new key stops working a few weeks after you program it?

Accepted Answer

Call me. That's what the warranty is for.

But also: if a correctly programmed transponder key on this generation stops starting the car, the key is rarely the culprit. What actually causes this pattern on older Foresters is the antenna ring around the ignition cylinder losing its connection, or the immobilizer control having an intermittent fault. The symptom is the engine cranks but won't fire, or cranks and immediately stalls, even with a key that worked fine the day before. If it starts sometimes and fails other times with the same key, that points to the vehicle side, not the key itself. I troubleshoot both.

Question 4

My 2012 Forester cranks fine but stalls immediately every time. Could this be an immobilizer problem?

Accepted Answer

Yes, and it's one of the more common misdiagnosis situations I run into. Crank-then-stall on this generation points strongly toward the immobilizer not completing its handshake with the transponder chip. The engine management gets a start signal but the security system cuts fuel before the engine can stay running. It feels mechanical, so people go down the fuel pump and injector rabbit hole first and spend real money before anyone checks the security side.

A few things cause this: a damaged chip in the key head, a failing antenna ring around the ignition cylinder, or an immobilizer that has lost its key data for reasons that aren't always obvious. If the key-warning indicator on the dash stays on or flashes after the engine stalls, that's your confirmation. If you have a second working key and the car behaves the same way with both, the antenna ring or the immobilizer module itself is where to look. I can read the immobilizer status on site and tell you which side of the problem you're on before any parts get ordered.

Question 5

I found a replacement key blade online that looks identical to mine. Can I just get it cut and skip the programming?

Accepted Answer

The cut key will open the door, but it won't start the car. The blade and the chip are two separate things. A correctly cut blade with no programmed chip in it will crank the engine and immediately stall, or depending on the immobilizer state, won't crank at all past the starter. You need both: the blade cut to your specific locks and the chip enrolled to your vehicle's immobilizer. That's the complete job. One without the other is half a key.

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