2007 Saturn SKY
Key Replacement - Save vs Dealer in Ventura County

The key head contains a small chip. When you insert the key and turn it, the ignition coil ring around the cylinder energizes that chip passively, no battery needed. The chip responds with a code. The immobilizer checks that code against what it has stored. If it matches, the engine is allowed to start. If it doesn't match, or if the chip is absent, the car will crank but not fire, or in some cases won't crank at all. When all keys are lost, we clear the old stored codes through the OBD port and enroll the new key so the immobilizer recognizes it. On a spare-key job where a working key already exists, some GM vehicles from this era support an onboard sequence that lets us add the new key without a scan tool. We figure out which path applies before we start cutting anything.

Yes, and it comes up more than people expect on older sports cars that see a lot of use. Extraction first, then a close look at the cylinder. A key that breaks and comes out clean usually leaves the wafers alone. One that gets forced or dug at before someone calls me can bend those internal wafers and cause the cylinder to stick or not return from the start position. I assess that on site. If the cylinder is fine, we cut a new key and program the chip and you're done. If the cylinder took damage, I'll tell you straight and we can handle that too, same visit if the parts allow.

Cranks-but-won't-fire with a security light is a classic sign the immobilizer didn't read the chip. A few things cause it. The chip itself can fail. The ignition coil ring around the cylinder can go bad and lose the ability to read the key. Or the key was cut to the wrong profile and turns the cylinder without the chip sitting close enough to the reader. Check the obvious first: is the key a copy of a copy? Worn blanks and re-cut keys sometimes have chips from incompatible families that almost work. If you have a second key, try it. If the second key starts it fine, the first key's chip has failed. If neither key starts it, the coil ring or the immobilizer control side is worth looking at. [/FAQ4_Q] [FAQ4_A] Cranks-but-won't-fire with a security light is a classic sign the immobilizer didn't read the chip. A few things cause it. The chip itself can fail. The ignition coil ring around the cylinder can go bad and lose the ability to read the key. Or the key was cut to the wrong profile and turns the cylinder without the chip sitting close enough to the reader. Check the obvious first: is the key a copy of a copy? Worn blanks and re-cut keys sometimes have chips from incompatible families that almost work. If you have a second key, try it. If the second key starts it fine, the first key's chip has failed. If neither key starts it, the coil ring or the immobilizer control side is worth looking at.

That is the smartest call you can make with a single-key vehicle. Getting a spare cut and programmed while you still have a working key is faster and often less expensive than an all-keys-lost job. All-keys-lost requires clearing the existing key memory and re-enrolling everything from scratch, which takes longer and needs more from the diagnostic side. Spare-key jobs on GM vehicles from this era are cleaner. Get the spare made, test it, put it somewhere it won't get lost, and you've bought yourself real insurance.