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Discussion Starter #1
I have a 323I E46 the transmission warning light is on.
analysis has indicated a brake light switch malfunction sensing brake on.
The original brake light switch operated the brake lights fine but have replaced with new oem switch and adjusted it correctly, Brake lights operate normally.
The warning light is still on and indicating a brakes on signal, this disables the cruise control and the transmission lock. (the transmission lock functions when ignition is off but requires no application of brake pedal when ignition is on as it senses a permanent brakes on condition)
I have cleaned all accessible connectors, checked all fuses, cleaned MAF sensor.

What can cause the Transmission Control unit to sense a permanent brakes on signal??
 

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IT sounds like a faulty brake light switch. There are multiple outputs from the switch. One output is for the light, the other for DME etc. I've seen this on a number of occasions with new brake light switches where one output is OK but the other is faulty.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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On the face of it, I'd tend to agree with the switch being faulty. Could also be electrical/wiring.

Any owner should have INPA anyway, so they can test/read values/diagnose.

If you look over to the wiring diagrams, you will see that the brake light signal is used by many components, for such I'd recommend genuine.
 

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2004 330Ci 85k miles
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Discussion Starter #9
On the face of it, I'd tend to agree with the switch being faulty. Could also be electrical/wiring.

Any owner should have INPA anyway, so they can test/read values/diagnose.

If you look over to the wiring diagrams, you will see that the brake light signal is used by many components, for such I'd recommend genuine.
Thanks for your input.
What is required to set up INPA to connect to the under bonnet 20 pole round connector?
 

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E30M3 Race F10 535 R1150Rt M Coupe
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This is the purvey of others, I am bereft of knowledge on such. I use factory ISTA P&D with my subscription to BMWs servers.
 

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2004 330Ci 85k miles
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What is required to set up INPA to connect to the under bonnet 20 pole round connector?
Get a 20-pin to 16-pin adapter like this: Scanner Adapter Cable
Hit the How to Install BMW Standard Tools link in my signature and follow the steps.
 
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