09 tdi electrical issues, radio dome light turn on for no reason

[4 TUGGIN]

have a 09 Jetta TDI. Far as I can remember, when car was new the radio would stay on after the ignition was turned off and stayed on until key was removed from ignition. A few years later the radio turns off when the car is turned off and if the key is left in ignition the radio will turn on hours later by itself. Also dome light comes on and off by itself. Drained battery several times by not taking key out of ignition. Any ever seen or heard of this? Has to be some sort of relay linking this stuff together and letting them power up with key in off position but still in ignition. Any info would help!

 

[D-Cell_Mekanick]

have a 09 Jetta TDI. Far as I can remember, when car was new the radio would stay on after the ignition was turned off and stayed on until key was removed from ignition. A few years later the radio turns off when the car is turned off and if the key is left in ignition the radio will turn on hours later by itself. Also dome light comes on and off by itself. Drained battery several times by not taking key out of ignition. Any ever seen or heard of this? Has to be some sort of relay linking this stuff together and letting them power up with key in off position but still in ignition. Any info would help!

Sounds haunted, lol. If you want I can scan it for you to see whats going on. Probably defective radio no allowing the cecm to go to sleep after 15 mins. But a scan should point ya in the right direction.

 

[FowVay]

Many '09 Jettas came from the factory with faulty ignition switches. I own one of those vehicles. I haven't had any trouble with my ignition switch but i do get four fault codes for the switch every time I do a VCDS scan. When I start having issues I will replace the switch.

You may also be having issues related to the problem. A VCDS scan might lead you in the right direction. If it is the switch then know that it isn't expensive to replace.

 

[oilhammer]

Yep, needs an ignition switch. Technically it is more like a "key position sensor" than a simple switch. Sends a low-voltage signal to and from the Steering Column module, which in turn communicates to the Central Electronics (along with the stalk switches, steering wheel bits, air bag connector, etc.).

There is a TSB about it, but I think even the p/n listed in there has been superceded, and I have seen this problem on cars that were NOT even listed in the TSB's VIN range.

 

[D-Cell_Mekanick]

Wow, didn't know there was a problem with the newer MKV ignition switches. I've heard of the older MKV switch failing when the piece of plastic inside wouldn't allow the key in. I must have missed those threads thinking the problem was the same.

 

[oilhammer]

The A5 has a 100% different ignition switch arrangement than the A4, and the A4 has a 100% different ignition switch arrangement than the A3. The A3 is the same as the A2, except the A2s rarely ever failed.

So much for product improvements, eh?