996.2 Ignition switch proper operation (power cut while starting)
 

Folks,

Tried searching, but couldn't find this exact question.

When I turn the ignition switch from the ON position to the START position (to start the motor), is the accessory and/or power lines to the radio supposed to go dead? I haven't checked it with a multimeter yet, but here are the symptoms:

1. Turn on ignition to ON, my new Sony radio (double-DIN) takes a while to boot. It works fine.
2. Start the car. During this, the power (always-on and/or accessory, I haven't checked yet) to the radio goes OFF.
3. The car starts and the Sony comes back from a black screen, but since it was so short, it doesn't reboot (it isn't going all the way back to the Sony boot logo). BUT THE VOLUME IS DEAD.

This is really a Sony problem... it's trying to come back from the power loss without a full reboot, but it's obviously messed up. In order to recover I have to turn off the car, wait several seconds, and then start it by going directly from OFF to START, allowing the Sony to only full boot after the car is started.
My working theory is that either the always-on battery connection or the accessory connection or both are going dead when turning the car over, and that the Sony can't handle this.

Question is: Is the power operating normally? Should accessories or always-on power (as measured at the connection to the head unit) be temporarily dropped during startup? Could this be an ignition switch problem or is it working as designed?

Thanks, experts!

Can't 100% confirm all of this for you at the moment. But i can tell you that my 04 C4S is exactly the same. While installing a double din over the weekend i noticed while just key on but not running the radio boots up and works. But when i fire the engine the radio and other accessories will die momentarily. I have a Kenwood, it has no issue with reboot. But my car does the same.

Realistically you should not have an issue since it is not often you turn the key on, wait 15 seconds and then fire the engine. As long as you are jumping in and hitting the key it should be no issue.

I think your issue is not really the boot up, more the turn off. These stupid advanced radios actual take 10 seconds to shut down after key off. I think your issue is that the unit was on, then when you fired the engine that power off/on so quick was the problem. If that make sense.

Thanks for the input. It would make sense for a car to do this in order to reduce load while starting, I just want to confirm proper operation.

Now to check with Sony about it!

All of this makes sense. It's just that, for example, my F-150 with factory double-DIN doesn't have this problem. I should be able to turn my car on and, say, look at the electronic dipstick, or maybe pull up directions to where I'm headed before I start my motor. I shouldn't then have to remember to turn off the car and wait 10s or whatever.

I don't think it's a Porsche problem, it's a Sony problem. If the radio stays up (doesn't require a full boot), it shouldn't forget about my volume.

It could also be the cheap Chinese Longate adapter. Now THAT is a distinct possibility. The Sony could be fine but the Longate could be confused.

I agree with all that you said. Turning it on long enough to check my oil and then firing it dosen't effect my kenwood. Yes it will restart, but no ill effects. Sony's got some explaining to do.

Just out of curiosity, does your Kenwood do a full reboot or does it come back up quickly?

Full boot. But it only takes maybe 10 seconds from off to ready at any given point.

I am going to try this: I'll put a power switch (temporarily) inline with the Longate MOST adapter. After reproducing the problem, I'll power off the adapter for 10 seconds, and power it back on. If the volume comes up, then it's a Longate problem and not a Sony problem. This is the easiest thing for me to do, just run a single pole switch on a long wire pair to the adapter. Something for me to do next weekend.

Didn't think about that. My car no longer has any aspect of the MOST system.

haha, that's where this could be leading someday too!