Just wondered if anyone knows about gearbox ecu issues?

My e46 323i has a problem with the brake light switch which I've been told is related to a fault in the gearbox ecu.

Apparently even though the brake switch is fine the ecu is showing the brakes as being on and therefore recording a fault.

My garage is saying that a new gearbox ecu is the only solution and it has to be programmed to the car by BMW, meaning a £1,000 bill.

Does this sound right? I've seen secondhand 'box ecu on the bay for £70.

Your garage clearly is talking well beyond their level of capability.

Just because an ECU flags a code it does not automatically mean that parts need changing. Correct interpretation of the code and appropriate diagnostics lead to a quality repair.

I would take the car to a franchised BMW dealer and have them diagnose the issue. It could be something as simple as a bad earth. It could be a wiring loom problem. Only decent diagnostics and thorough investigation of the issue will show where the fault truly is.