My stock radio acts as an immobilizer when code not entered, normal?

[noid]

After re-installing the original radio back in my E30, I have discovered that the radio in my car also acts an immobilizer for the car. If the code is not entered the car will crank but not start. With the code entered it will fire up immediately.

Is this normal? Was this standard on all radios and across all years?

As far as I can tell I have re installed the radio exactly as it should be (all wires colors matched).

[jlevie]

That is not normal and was never a feature to the best of my knowledge.

[noid]

After some intenese googling I came up with this, which talks about the same thing (they talk about the OBC not the radio though):

http://blog.bavauto.com/2973/bmw-obc-anti-theft-code-e23-e24-e28-e30-e32-e34/

[Lodsin]

Haven't heard of the radio doing that. I know the OBC has a fuel cut-off function, might want to dig deeper into your radio wiring. Or just never forget the code.

[defaultName]

OBC definitely but never heard of the radio doing that.

Keep us posted!

[Redfox]

Sounds like a pretty good antitheft system..

[StereoInstaller1]

Do you have the "Anti Theft Radio" manual?

I have one here somewhere I have never opened...

[noid]

I don't have the manual, the radio model is cm5907.