The grey Valet blank is different in two ways from the black Master blank. First, the Valet key does not have the groove down the sides of the key. This is supposed to prevent the key from physically entering the keyway of the trunk or glove box lock. Unfortunately, the glove box lock is mostly plastic, so it may not do a very good job of keeping the Valet key out.

The other difference is even more important. The transponder chip in a Master key is different from the chip in a Valet key. GM Passkey 3 systems require only one working transponder key in order to program a new duplicate key for use in that car, and that key must be a Master key. This is to prevent your valet from duplicating your key onto a blank key and then programming it to drive your car away later.

So, here we go... Is the head grey? Does it say Valet on the side of the rubber head? Does it have flat sides instead of grooved sides? Did you ever get a chance to try to slide the key into your trunk lock?

Please let us know what you find.