: Brake lights on constantly when engine running



dac675
04-29-10, 07:47 AM
This one has me stumped... My '07 V has lately been throwing an intermittent steering/stability message and locking out the ABS and stability control. By everything I have read to date it sounds like a SWPS issue, and I will be changing the sensor this weekend. This morning while the car was idling in the driveway I noticed the brake lights on with the car stationary and no pressure on the brake pedal. Drove the car to work and the lights were still on constantly when I checked. They shut off when the car shuts down, but if the engine is running, they are on (I assume whenever the key is in the on position)? Has anyone had a similar problem? Could this be related to my steering issue? Is there a relay or sensor that I should be checking? I could understand if something was stuck, but the fact that the lights go out when the car is off has be baffled...:bonkers:

ewill3rd
04-29-10, 07:53 AM
On all CTS the brake lights will not illuminate with the car off. They are run by a control module based on an input from the BPP or brake pedal position sensor.
The sensor must be calibrated so that the computer knows what position is "released".
The BPP is reporting that it thinks your foot is on the brake. You should just need to recalibrate the BPP, should be a quick fix using a Tech 2 in the DIM (dash integration module)...I think. I'd have to look it up to be 100% sure on which module it is an input to.

On a side note, some of the older CTS had a conventional brake switch but it was not powered with the key off so even though it is technically different, you still won't get stop lamps with the key off.