Power?
If you have any component in this ski go bad, it would be identified by a "p" code in your info center. Even if your MPEM (multi purpose electronic module) is bad, you'd know through the beeps when attaching your lanyard or through the info center.
Your lanyard and DESS system has got to make a complete circuit before the MPEM will allow power to your ski, for anything it controls.....including your accessories.
Before you go, I would check all fuses in your electrical boxes. In my Challenger model, I have to fuse boxes, one in the back at the engine compartment and one up front under the dash where my steering wheel is. I lift open the hood thing and pull out the box that has my fire extingushier an under it is another fuse block. Make sure you check all connections from your battery to your solenoid and the wires on the solenoid and your ground to the block. Because a lose connection will cause a total loss of power too. But if it's a new lanyard cap needed, an authorized Sea-Doo repair shop is the only one who can re-program a new key for it. Oh, and buy a couple extra and program. You can get up to 5.......
NOTE: I've looked for a test to check the ohms in your post, in the event you can replace it without going to the shop. The manual points out a test, but has a disclaimer that it's not for the DI models....I can't see why. Let's look at the post before you decide to take it in for a new key. When mine went out, it was the post. So I saved myself the headache of going in to the shop. Look at your post connector. I need to know how many wires you have at your connector. If you have three, I need to know the colors. Important, if one wire is black with a yellow strip going around it, then it's written like this.......black/yellow.
Also, the book does state the importance at this time with a power issue, to check all your plugs for corrosion ( the white powdery stuff in the connectors). Unplug all the connectors going to your mpem or inside your electrical box and look for corrosion. Have some die electric grease on hand and insulate with it. After pulling these plugs to your electrical box and plugging them back up, give it a try!.....and keep your fnigers crossed.
OH and very IMPORTANT...disconnect your battery before any electrical work is to be preformed!..........GOOD LUCK!